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Aquaculture Magazine Volume 45 Number 2 April - May 2019






on the


National Aquaculture Association Notes. Atlantic states farm-raised seafood consumer attitudes and preferences report released.



the Perfect Oyster Shell

Growth and development of skeletal anomalies in diploid and triploid Atlantic salmon (Salmo salar) fed phosphorus-rich diets with fish meal and hydrolyzed fish protein.


Corn gluten meal induces enteritis and decreases intestinal immunity and antioxidant capacity in turbot (Scophthalmus maximus) at high upplementation levels.



Countries and Experts Commit to Collaborate for the Sustainable Evolution of the Aquaculture Sector.

Volume 45 Number 2 April - May 2019

Editor and Publisher Salvador Meza info@dpinternationalinc.com


Local Food Systems and Market Opportunities for Aquaculture Products.

Editor in Chief Greg Lutz editorinchief@dpinternationalinc.com

Editorial Assistant Nancy Jones Nava editorial@dpinternationalinc.com


Recent News and Events

44 LATIN AMERICA REPORT Recent News and Events.


Understanding Fish Feed Labels.



Editorial Design Francisco Cibrián

Designer Perla Neri design@design-publications.com

Marketing & Sales Manager Christian Criollos crm@dpinternationalinc.com

Business Operations Manager Adriana Zayas administracion@design-publications.com

Subscriptions: iwantasubscription@dpinternationalinc.com Design Publications International Inc. 203 S. St. Mary’s St. Ste. 160 San Antonio, TX 78205, USA Office: +210 5043642 Office in Mexico: (+52) (33) 8000 0578 - Ext: 8578 Aquaculture Magazine (ISSN 0199-1388) is published bimontly, by Design Publications International Inc. All rights reserved. www.aquaculturemag.com

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Changing Tastes, Changing Minds. By Neil Anthony Sims

Making Sense of USDA Siluriformes Inspection. By: Evelyn Watts & Katheryn Parraga



The Cost of Regulations on U.S. Trout and Salmon Farms. By: Carole R. Engle, Jonathan van Senten and Gary Fornshell



Use of antibiotics in the major salmon producing countries. By Asbjørn Bergheim





Merrior – The Good Flavors of Oysters. By Michael A. Rice*

Recent news from around the globe by Aquafeed. com By Suzi Dominy



Ozone: Go Zone or No Zone? By Amy Stone



The aquaculture mentality… By C. Greg Lutz

Certain personality traits seem more frequently encountered among aquaculturists, no matter what part of the world you find them in, and certain terms come to mind when trying to describe them.


hile it’s not necessarily well-defined, many of us know the “aquaculture mentality” when we see it. It’s personified in many individuals and organizations that embrace the idea of producing something out of the ordinary, and in doing it in their own way. Although they all seem to have a pioneering streak, some aquaculturists are contemplative and inquisitive, while others charge head-on into their business ventures convinced they have a better way to get things done. And oftentimes they do. Any Extension professional that has worked in the aquaculture realm, on virtually any continent, can attest to that. Certain personality traits seem more frequently encountered among aquaculturists, no matter what part of the world you find them in, and certain terms come to mind when trying 4 »

to describe them. Hard headed. Inquisitive. Innovative. Entrepreneurial. Independent. And yet, like-minded producers often come together to share ideas and work for common goals. Whether catfish producers in Nigeria or trout farmers in the U.S., aquaculturists often find ways to develop producer associations because they recognize that rather than going it alone and reinventing the wheel, there is more to be gained from information exchange and speaking in unison to policy makers. However, for the purposes of discussion, regulation, marketing, or promoting the cash flows of innumerable NGO’s and environmental advocacy groups, the various segments of global aquaculture are often thrown together with very little in common other than water. Trout farming in Germany vs shrimp pro-

duction in Guatemala? Oyster farming in France vs tilapia cage production in Uganda? Crawfish farming in Louisiana vs game fish fingerling production in Iowa? It’s all just “aquaculture” in some people’s minds. And in spite of these brazen generalities, or perhaps because of them, we often find ourselves in the same boat (pun intended, I suppose). This eventuality is most notable at industry gatherings such as the recent Aquaculture America meeting in New Orleans. In some parts of the world, certain aquaculture industries are large enough and have sufficient economic and political impact to influence regional or national policy and regulations. Several examples come to mind, such as shrimp farming in Ecuador, Pangasius farming in Vietnam and Seabass and Sea Bream farming in the Mediterranean. But in places

The various segments of global aquaculture are often

thrown together with very little in common other than water.

like the United States and the European Union, diverse and fragmented industries need to stand together in order to be heard and taken seriously. And to make their case to consumers. And so in the minds of the public (and the regulators) we often become one “industry”. We can all agree that the public (and the public sector) are still not nearly as familiar with “aquaculture” as we need them to be, and the resultant costs in terms of policy, regulatory burdens and market growth are quite high at times. However, the costs of unfamiliarity among ourselves, as different segments of this somewhat artificial agglomeration, can be almost as high. While the “aquaculture mentality” tends to be associated with independent thought and initiative on an individual basis, for the foreseeable future we will all need to support the organizations that unite us, in spite of the diversity of species and production systems we bring together. In that light, the purpose of our magazine is to share experiences and ideas to the benefit of all.

Dr. C. Greg Lutz has a B.A. in Biology and Spanish by the Earlham College at Richmond, Indiana, a M.S. in Fisheries and a Ph.D. in Wildlife and Fisheries Science by the Louisiana State University. His interests include recirculating system technology and population dynamics, quantitative genetics and multivariate analyses and the use of web based technology for result-demonstration methods.




Fraudster guilty of fleecing public purse with ragworm ponds


n March 28, a man pleaded guilty to fraud after claiming up to £4.7m worth of European Union and Welsh Government grants. According to the Crown Prosecuting Service (CPS), Anthony Smith, 72, admitted three counts of fraudulent trading at Cardiff Crown Court. The grants relate to the companies Dragon Research Ltd, Dragon Feeds Ltd and Dragon Baits Ltd and their development of various projects involving ragworms. His deception involved claiming large sums of money to develop a plant to process ragworm for bait and ponds in which to rear them. Smith made false promises that prosperity would be brought to Port Talbot and Pendine in Carmarthenshire through the 120 new jobs. In reality, only seven positions were created. Smith dishonestly ran Dragon Research Ltd with Colin Mair, 68, who pleaded guilty to fraudulent trading on February 4. They were assisted by Keith Peters, 72, now a retired chartered accountant, who admitted two counts of false accounting. Janet Potter, for the CPS, said: “Not only did Anthony Smith wildly

overstate how much money had been spent, but he made up stories about projects which never existed. “He did this all under the guise of being environmentally-friendly and boosting the local economy. “He promised to make Wales a world leader in the aquaculture industry, but instead he abused the system and robbed the local community of investment.” The case has been adjourned for sentence to 10 May 2019. At the heart of the prosecution case was proving

that Smith knowingly and willfully misused government funds. The CPS used specialist software to interrogate financial records belonging to the Welsh Government. It also reviewed seven million items of digital material to ensure there was nothing to undermine the case. In addition, a forensic accountant was hired to review financial accounts, which enabled the CPS to prove that Smith had deliberately structured the business in order to hide the flow of illegitimate funds.

Subcommittee on Aquaculture’s Science Planning Task Force develops draft outline of Science Planning Task Force


he Subcommittee on Aquaculture (SCA), previously known as the Interagency Working Group on Aquaculture, serves as the federal interagency coordinating group working to increase the overall effectiveness and productivity of federal aquaculture research, regulation, technology transfer, and assistance programs. The subcommittee includes members from NOAA, USDA, EPA, Army Corps of Engineers, and other fed6 »

eral agencies. The current work plan for the group was approved by the Office of Science and Technology Policy and can be found at: https://www.ars.usda.gov/SCA/ Documents/Subcommittee%20 on%20Aquaculture%20Workplan. pdf ?utm_medium=email&utm_ source=govdelivery The Science Planning Task Force of the SCA has recently developed a draft outline, that can be downloaded here: https://

www.ars.usda.gov/SCA/Task%20 Forces%20and%20Working%20 Groups/2019%2003%202519%20 NSPFAR%20Outline%20DRAFT. pdf ?utm_medium=email&utm_ source=govdelivery The SCA will continue to seek public input and foster engagement on future work products that aim to increase aquaculture opportunities and regulatory efficiency. To learn more about the SCA visit www.ars. usda.gov/SCA/index.html .

USDA Launches Online Assistance with Farm Loans and H-2A Visas


he U.S. Department of Agriculture (USDA) recently launched two new features on farmers.gov to help customers manage their farm loans and navigate the application process for H-2A visas.

Managing Farm Loans Online: The self-service website now enables agricultural producers to login to view loan information, history and payments. Customers can access the “My Financial Information” feature by desktop computer, tablet or phone. They can now view: • loan information; • interest payments for the current calendar year (including year-to-date interest paid for the past five years); • loan advance and payment history; • paid-in-full and restructured loans; and • account alerts giving borrowers important notifications regarding their loans.

To access their information, producers will need a USDA eAuth account to login into farmers.gov. After obtaining an eAuth account, producers should visit farmers.gov and sign into the site’s authenticated portal via the “Sign In / Sign Up” link at the top right of the website. Currently, only producers doing business as individuals can view information. Entities, such as an LLC or Trust, or producers doing business on behalf of another customer cannot access the portal at this time, but access is being planned.

Navigating the H-2A Visa Process: Focused on education and smaller owner-operators, this farmers.gov H-2A Phase I release includes an H-2A Visa Program page and interactive checklist tool, with application requirements, fees, forms, and a timeline built around a farmer’s hiring needs.

The H-2A Visa Program – also known as the temporary agricultural workers program – helps American farmers fill employment gaps by hiring workers from other countries. The U.S. Department of Labor, U.S. Citizenship and Immigration Services, U.S. Department of State, and state workforce agencies each manage parts of the H-2A Visa Program independently, with separate websites and complex business applications. Over the next several months, USDA will collaborate further with the U.S. Department of Labor on farmers.gov H-2A Phase II – a streamlined H-2A Visa Program application form, regulations, and digital application process that moves producers seamlessly from farmers. gov website to farmers.gov portal to U.S. Department of Labor’s IT systems.




Irish Government Inaction Leads to 21% Drop in Aquaculture Production


he Chairman of the Irish Farmers’ Association (IFA) Aquaculture section, Michael Mulloy, has criticized the Department of Agriculture, Food and the Marine’s lack of support and failure to promote Irish aquaculture production in light of a report which shows output levels plummeting here. The most dramatic fall was in salmon production where 12,200 tonnes of fish were produced last year, which represents a dramatic 39% reduction on the previous year. According to Mulloy, “’The Business of Seafood 2018’ report, soon to be published by Bord Iascaigh Mhara (BIM), will show that salmon production accounts for more than 67% of the overall value of the Irish aquaculture industry. “We are now asking the Department how many finfish licenses have been issued in the last five years and how many applications are waiting in the system? IFA is aware of applications which were submitted in 2005 which still haven’t been processed 14 years later. This ongoing lack of progress with new licenses as well as renewals rests with the Department. It also raises serious questions about the effectiveness of BIM.”

Mr. Mulloy added, “Aquaculture is a significant and very valuable source of employment in rural, coastal communities where alternative sources of employment are limited.” Almost two years ago, the Minister published the eagerly anticipated report of the Independent Aquaculture Licensing Review Group which outlined 30 recommendations to improve a dysfunctional regulatory system, but he has implemented few, if any, of the actions outlined within. Ireland’s failure to meet the targets has had a critical impact on the aquaculture sector. The opportunity to create and sustain 1,300 jobs has

been wasted. According to BIM’s figures, Irish aquaculture is now 20% below 2010 volumes and based on Government targets of 7.8% yearly growth, this means the industry is a staggering 82% below stated Government policy targets. Michael Mulloy said IFA is seeking to establish clearly just what the Department intends doing about the missed opportunity and subsequent decline in Irish fish production. “We’ve seen report after report, review followed by review and all the while, the industry is contracting. The time for talking is over, this sector needs real action,” he said.

USDA Announces 2019 Aquaculture Research Grants Opportunity


he purpose of the Aquaculture Research program is to support the development of an environmentally and economically sustainable aquaculture industry in the U.S. and generate new science-based information and innovation to address industry constraints. Over the long term, results of projects supported by this program may help improve the prof8 »

itability of the U.S. aquaculture industry, reduce the U.S. trade deficit, increase domestic food security, provide markets for U.S.-produced grain products, increase domestic aquaculture business investment opportunities, and provide more jobs for rural and coastal America. The Aquaculture Research program will fund projects that directly address major constraints to the

U.S. aquaculture industry and focus on one or more of the following program priorities: (1) genetics of commercial aquaculture species; (2) critical disease issues impacting aquaculture species; (3) design of environmentally and economically sustainable aquaculture production systems; and (4) economic research for increasing aquaculture profitability.

Two types of applications are available: Standard project proposals: The intent is to fund applied research that addresses program priorities with a maximum total award of $300,000 and maximum duration of 2 years. Seed project proposals: For FY 2019, a new category was added for smaller, research seed projects that total between $50,000 to $100,000 and are limited to 1-year duration (except in rare circumstances). Eligible Applicants: Applications may be submitted by State agricultural experiment stations, all colleges and universities, other research institutions and organizations, Federal agencies, private organizations or corporations, and individuals for the purpose of conducting research, extension, or education activities to facilitate or expand promising breakthroughs in areas of the food and agricultural sciences of importance to the United States. Dates: April 29th, 2019 - A Letter of Intent (LOI) is highly encouraged and should be received by 5:00 p.m., Eastern Time May 28, 2019 – Full applications must be received by 5:00 p.m. Eastern Time. Other key information: This program is limited to applied research. Applications must include U.S. aquaculture industry involvement. This can include, but is not limited to, a U.S. aquaculture producer as a co-project director or partner or assembling an industry advisory committee for the project (e.g., a farmer’s advisory committee for the project that can also include producer-based organizations, feed manufacturers, animal health industry, etc.). Applications must clearly state how the research results or technology developed will be transferred to end-users outside of direct, scientific peers.

Applicants must clearly describe how their specific research project will increase U.S. aquaculture production or profitability in the short or medium-term (1-5 years after the grant ends). For the critical disease Program Area Priority, proposals that focus on pathogens that pose a risk to humans or human food safety (vs. those that affect the health of an aquaculture species) are outside the scope of this program and will not be accepted or considered for review. Applicants must provide a plan to release research results to the public in a timely manner and provide a description and budgeted plan for the release of research results that is compliant with the terms and conditions that govern USDA NIFA-funded projects in aquaculture. Terms and conditions can be found at: https://www.nifa.usda.gov/business/awards/awardterms.html. Applicants must include statistical power analyses, when appropriate, and describe the experimental design, experimental unit, replication

and sample size for each experimental group. Applicants are strongly encouraged to review the American Fisheries Society (AFS) document, Guidelines for the Use of Fishes in Research (2014), when developing applications. The inclusion of students actively engaged in the scholarship of the research projects is strongly encouraged (particularly undergraduate student interns and trainees, graduate students, and post-doctoral research associates) to provide hands-on, experiential learning and training opportunities. Actively engaged students should be encouraged to contribute to presentations, articles, posters, and other expressions of scholarship that reflect their own work on the project. Matching support is no longer required for the Aquaculture Research program. For complete information and/ or to apply, visit: https://www.nifa.usda.g ov/ funding-opportunity/special-research-grants-program-aquacultureresearch Âť



National Aquaculture Association Notes

Atlantic states farm-raised seafood consumer attitudes and preferences report released


he Atlantic States Consumer Seafood Survey was conducted during the summer of 2018. Data were used to build an online tool that allows users to explore seafood markets by state, sub-region, and region by category and species. The project was conducted by Atlantic Corporation, an agricultural business and economic research and development company based in Waterville Maine in collaboration with an extended team of industry experts. An extensive 30+ question survey was designed by the team and reviewed by three external aquaculture experts, two from the mid-Atlantic sub-region and one from the southeast sub-region for balance. The online survey was hosted and administered by QualtricsÂŽ and resulted

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in 5,989 completed surveys, with at least 400 from each of the 14 Atlantic states, during July and August, 2018. The Maine Statistical Analysis Center analyzed the data. Nutrition was rated the top benefit of finfish and sea vegetable aquaculture, while local economies and nutrition were considered benefits of shellfish farming. Wild-caught finfish and shellfish were preferred, but the majority of respondents had no

preference for sea vegetable production method. These and other findings can help businesses engaged in farm-raised seafood for human consumption develop sales and marketing plans based on market demand. Opportunities exist to expand U.S. aquaculture production to improve public health, stimulate local economies, and offset foreign seafood imports. The development and implementation of data-driven marketing strategies can enhance the success of businesses providing farm-raised seafood for human consumption. While the allocation of resources to design and build sound infrastructure to support a young and growing industry is of great importance, ensuring the financial health of individual firms within the industry is reliant on operating with a business model that is to some extent market-driven. This research was supported by the National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The Consumer Attitudes and Preferences about Farm-Raised Shellfish, Finfish, and Sea Vegetables in the Atlantic Coast States report and online spatial tool are available at: www.atlanticcorp.us/ reports.

teams from all over the world. The Team has subsequently applied for a provisional patent and are requesting comments from the aquaculture community on their design. To see the team, their design and to complete a short survey, visit http:// www.lmsrobotics.org/home/Shrimpartment.

Student Robotics Team Farming Shrimp in a Galaxy Far, Far Away Benefiting from comments by a variety of aquaculture experts, including the National Aquaculture Association, a student robotics team from Lincoln Middle School, located in Mount Prospect Illinois, has swept the FIRST® Lego Regional Tournament and State Championship to advance to the FIRST® World Festival. Team 492, The Shrimp Strike Back, designed a production system to grow shrimp in space. Team 492 excelled at the FIRST® Lego Re-

gional Tournament. They received a Champions Award for excellence in all three parts of the competition: Robot, Project, and Core Values. Winning the regional competition qualified the team to compete in the Illinois State Championship where they earned the 1st Place, All Around Champion’s Award, the highest honor available to any team. They are now into the Orbit journey to the FIRST® World Festival in Detroit, Michigan during April 2019. The World Festival is a competition that showcases the best FIRST®

Striped bass. Photo: U.S. Fish and Wildlife Service, National Digital Library

NAA Recognizes US Aquaculture Leaders with McCraren Awards During Aquaculture 2019, the National Aquaculture Association (NAA) recognized two individuals from the US aquaculture community with Joseph P. McCraren awards. These individuals go far beyond their everyday responsibilities to constructively and thoughtfully grow US aquaculture. The Joseph P. McCraren Lifetime Contributions to US Aquaculture award was presented to Mike Freeze. Mike has devoted countless hours and dollars over 40 plus years to enhancing, expanding and influencing US Aquaculture in a dynamic and positive way to the benefit of the aquaculture community, state and federal elected representatives and government agencies. He started with a state agency, partnered with two people to build the largest hybrid striped bass production hatchery in the United States, and became a major producer of triploid grass carp as well as many other species. Building a 1000-acre farm and business from scratch is daunting to anyone and speaks volumes of his capabilities to learn, excel and succeed. With the help of his very capable partner, Martha Melkovitch, Mike Freeze has quietly and without fanfare contributed and shaped advocacy efforts to benefit US aquaculture. He was an early and strong advocate for creating the National Aquaculture Association serving as the NAA’s first President, and 7 total terms as President, and continues to provide his wisdom and council as a member of the Board of Directors and several NAA committees. » 11


The Joseph P. McCraren Outstanding Contributions in Promoting the Growth of Aquaculture award was presented to Sebastian Belle, Executive Director for the Maine Aquaculture Association. Sebastian is a consistently strong and thoughtful advocate for aquaculture locally and at the state, regional and international levels. His keen knowledge and experience in forging new partnerships and his entrepreneurship background have sparked the development and successful growth of aquaculture within his state. He has also been an excellent spokesperson and sound voice for the US aquaculture community. He draws upon an extensive and varied career in fisheries, aquaculture, state government and business when representing the industry, and has honed his skills in communications, marketing and politics to contribute to the growth of US aquaculture. Please join the National Aquaculture Association in celebrating and congratulating Mike Freeze and Sebastian Belle as recipients of the 2019 Joseph P. McCraren awards.

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Agricultural Improvement Act Of 2018: Relevant Farm Bill Animal Health Provisions The summary pasted below provides a brief overview of the APHIS animal health related provisions in the new Farm Bill: SEC. 12101. ANIMAL DISEASE PREVENTION AND MANAGEMENT. • Establishes the National Animal Disease Preparedness and Response Program (NADPRP), which allows USDA-APHIS to enter into cooperative agreements with states, universities, industry and other entities on projects and research to advance animal health. • Establishes the National Animal Vaccine and Veterinary Countermeasures Bank (NAVVCB) to maintain sufficient quantities of vaccine and other countermeasures to help address an outbreak of foot-and-mouth disease or other high consequence foreign animal diseases. • Reauthorizes the National Animal Health Laboratory Network (NAHLN) with authorized appropria-

tions up to $30 million per year. • Provides $30 million annually in mandatory Commodity Credit Corporation funding for all three animal health programs. Funding for the first four years ($120 million) is provided up front as no-year money. • Of the funding provided, NADPRP must receive a minimum of $5 million for the first four years, and $18 million (of the $30 million) annually after that. SEC. 12105. NATIONAL AQUATIC ANIMAL HEALTH PLAN. • Removes the specific authorization for appropriations, effectively making the program permanent. SEC. 12106. VETERINARY TRAINING. • Adds “and veterinary teams, including those based at colleges of veterinary medicine,’’ to the existing authority for the secretary to maintain a program to train sufficient numbers of veterinarians on the diagnosis of foreign animal diseases under 7 USC 8318.

spring viremia of carp virus (SVC), and infectious pancreatic necrosis virus (IPN). • The facility has a biosecurity plan. • There has been no unexplained morbidity/mortality prior to export, and no official disease restrictions have been placed on the exporting facility. • The populations have not been in contact with water or animals of a lesser or unknown health status. • The animals have not been vaccinated for the diseases of concern.

SEC. 12204. BIOLOGICAL AGENTS AND TOXINS LIST. • When evaluating whether a select agent or toxin should remain on the list, USDA-APHIS should consider the value that removing it would have on research activities for animal and plant diseases.

Koi Exported to Canada Subject to New Animal Health Requirements As a result of outbreaks of koi herpesvirus disease (KHV) in Canada in 2018, new requirements to export koi carp from the United States to Canada will go into effect on April 15, 2019. In addition to testing requirements for US-raised koi, the new koi export health requirements will no longer allow imported koi into the United States to be re-exported to Canada without prior testing conducted in the United States. These requirements are listed on a new model health certificate which

applies exclusively to the export of koi carp (Cyprinus carpio) from the United States to Canada. In 2018, the Canadian Food Inspection Agency (CFIA) notified the US Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) of their intention to add import requirements for koi carp. Based on input from industry stakeholders, APHIS has negotiated with CFIA to establish requirements in line with industry practices wherever possible. A summary of these new requirements is as follows:

EITHER The exporting premises can be designated as free from the diseases of concern if the USDA accredited veterinarian can verify that: • The facility has historical testing and ongoing testing conducted in the United States to support freedom from CFIA regulated diseases in koi: koi herpesvirus (KHV),

OR If the premises cannot meet the statements listed above, then the population to be exported: • Has been tested in the United States, and found free of the diseases of concern (KHV, SVC, IPN). • Has had no unexplained morbidity/mortality prior to export, and no official disease restrictions have been placed on the exporting facility. • The animals to be exported have not been in contact with water or animals of a lesser or unknown health status. • The animals have been inspected and showed no clinical signs of disease. • The animals have not been vaccinated for the diseases of concern. Importantly, there is no change in the export certification requirements for any other ornamental or aquarium species (including goldfish), and these species will continue to use the existing export certificate entitled “Live Ornamental Aquatic Animals Intended for Commercial Aquarium use in CLOSED Premises in Canada.” If you would like to speak to USDA APHIS about how your premises can comply with these new requirements, please contact the Export Animals staff at (301) 8513300, Option 2, and request to speak to the Aquatics Subject Matter Expert or the Staff Officer for Exports to Canada. » 13


Growth and development of skeletal anomalies

in diploid and triploid Atlantic salmon (Salmo salar) fed phosphorus-rich diets with fish meal and hydrolyzed fish protein By: Stefano Peruzzi , Velmurugu Puvanendran, Guido Riesen, Rudi Ripman Seim, Ørjan Hagen, Silvia Martínez-Llorens, Inger-Britt Falk-Petersen, Jorge M. O. Fernandes, Malcolm Jobling *

The induction of triploidy represents the most common and reliable method for the production of sterile fish. Efforts to produce functionally sterile stocks relate to the potential association with improved postpubertal somatic growth, survival and flesh quality.


terility is also a management tool for the genetic containment of cultured fish in the event of accidental escapes or targeted stocking and introductions into natural waters. Triploid Atlantic salmon (Salmo salar) are often reported to have a higher incidence of skeletal deformities than diploids, and there is evidence that the proportions of triploid fish with skeletal abnormalities can be reduced by changing diet formulations. In particular, triploids may have higher dietary requirements for phosphorus and protein than diploids, and there may also be differences in amino acid requirements and metabolism. There are also dissimilarities in the morphology of the digestive system of diploid and triploid Atlantic salmon and these might have an influence on digestion and absorption, and subsequent nutrient utilization and growth. Hydrolyzed fish proteins have high concentrations of free amino acids and low molecular peptides that

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may be absorbed relatively easily, and these could have a subsequent influence on nutrient utilization and fish growth. Protein hydrolysates produced from fish and fish by-products have been used as feed ingredients for a number of farmed species, including Atlantic salmon. In this study, the performances of diploid and triploid salmon reared at low temperature and fed a highprotein phosphorus-rich fishmealbased diet were compared with those of salmon fed a similar diet containing a high proportion of fish protein hydrolysate. Fish were examined at regular intervals, from start-feeding until the completion of parr-smolt transformation, with records being made of survival, growth, and skeletal deformities. Expectations were that the combination of low-temperature rearing and feeding a high-protein phosphorus-rich diet containing hydrolysed fish proteins might alleviate some of the problems associated with the development of skeletal deformities in triploid salmon.

Materials and Methods Eggs from twenty female Atlantic salmon were fertilized with milt from thirteen males (Stonfiskur, SalmoBreed AS, Iceland), each female being crossed with either one or two males resulting in full-sib and half-sib families. At 300°-min postfertilization at 5°C, half of the fertilized eggs from each female was subjected to a hydrostatic pressure shock (TRC-APV; Aqua Pressure Vessel, TRC Hydraulics Inc., Dieppe, NB, Canada) of 9500 psi applied for 5 min to induce triploidy. The remaining eggs served as diploid controls, giving 40 groups in total (20 diploid and 20 triploid). The eyed-eggs (ca. 400 degree-day, dd) were shipped to the Tromsø Aquaculture Research Station, Norway (69°N, 19°E). Diploid and triploid families were held in separate incubation trays (n = 40) in a flow-through system at an average temperature of 4.8°C (minimum: 3.9°C, maximum: 5.8°C) following standard rearing procedures. Upon hatching, ploidy status of the fish was verified by flow cytometry using 20 and 50 newly-hatched fry from each diploid and triploid family, respectively. Three out of the twenty triploid families had small percentages (2–5%) of diploid fry and were discarded along with their diploid counterparts. Just prior to start-feeding, equal numbers of individuals for each ploidy within each of the 17 families were pooled and allocated to twelve 200 L circular indoor tanks (ca. 3000 fish per tank, and tank biomass ca. 620 g). Triplicate tanks per ploidy were fed a standard fish meal (STD) diet or a modified diet in which 45% of the fish meal fraction was replaced with hydrolysed fish proteins (HFM) (Skretting AS, Stavanger, Norway). Phosphorus concentrations in STD and HFM diets were analysed (MasterLab, Boxmeer, Netherlands) to be 19 g kg-1 and 18 g kg-1, respectively, which is considerably in excess of the reported requirement of Atlantic salmon (8 g phosphorus kg-1

Table 1 Formulation and chemical composition of the diets.

diet). An inert marker (yttrium) was added to the largest pellet (3 mm) of each diet (10 g kg-1) for analysis of dietary digestibility. Feed was delivered via electrically driven disc feeders programmed to supply 6–9 meals each day, and the amount of feed provided was always in excess of that consumed. At the onset of start-feeding, water temperature was gradually increased to 10°C over a period of 4 weeks and was maintained at this level using heated water (10.0 ± 0.5°C), except during the summer (04 July– 02 September) when fish were exposed to ambient water temperature (range 9.5–12.5°C). General husbandry conditions followed standard in house procedures for Atlantic salmon. Fish were transferred from 200

L to 500 L tanks on 20 May and reared under constant light (LL) throughout the experiment except for the period 06 September—18 October when 12h light (12L:12D) was used to simulate winter conditions and induce parr-smolt transformation. Fish had completed parrsmolt transformation by the end of the experiment on 15 November. Fish growth in each tank was calculated from biomass increase during the course of four periods (Periods 1–4) covering 0–2745 degree-days post start-feeding (ddPSF). At these times biomass re-adjustments were made to maintain tank biomass below 40–45 kg m-3. The total weight of fish (biomass) in each tank was recorded and the mean body weight (MW g) and numbers of fish pres-

ent estimated by taking three random subsamples of 50 fish from each tank. Estimate of growth and condition factor were also obtained by measuring individual body weight (IW g) and fork length (FL cm) of 25 fish per tank at ca. 4 week intervals, beginning at 2 weeks after startfeeding (95 ddPSF). At the parr stage (1390 ddPSF), 100 fish per tank were visually inspected for externally detectable deformities to the operculum, jaws (i.e. misalignment, shortening, downward curving) and spinal column. At the end of the experiment (2745 ddPSF), 40 fish from each tank (n = 120 fish/group) were inspected for externally detectable deformities and then radiographed to detect lower jaw deformity and skeletal

Table 2 Fish growth assessed using thermal growth coefficient.

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ARTICLE Table 3 Apparent digestibility of diets.

(vertebral) anomalies (i.e. number, type and location). The spinal column was divided into four regions (R): R1 (cranial trunk) covering vertebrae (V) V1-V8, R2 (caudal trunk) covering vertebrae V9-V30, R3 (tail) covering V31-V49, and R4 (tail fin) covering V50-V58 to V60. Individuals with at least one deformed vertebra were classified as deformed and the type of deformity was noted. Numbers of vertebrae were recorded for each fish and when two or more fused vertebrae were seen each was counted. Deformities of the spinal column were further characterized by measuring the ratio between the distance from the tip of the head to the posterior edge of the dorsal fin, and from the posterior edge of the dorsal fin to the caudal peduncle as indices of shortened trunk (STR) and shortened tail area (STA). Lower jaw deformations were recorded and

assessed by calculating the lower jaw index (LJI) as: LJI = L2/L1, where L1 and L2 represent the distance (pixels) between the articulation point of the pectoral fin and the tips of the upper and lower jaws, respectively. Apparent digestibility coefficients (ADCs) of dietary protein, fat, phosphorus and calcium were measured at the end of the experiment. For this purpose, 5 fish per tank were sacrificed, gastrointestinal tracts were removed following dissection and digesta from the rectum transferred into Eppendorf tubes, and frozen at -80°C until analysis. Diets and faecal samples were analysed for dry matter, crude fat, crude protein, phosphorus, calcium and Yttrium. Chemical compositions of diets and faeces were analysed for dry matter (DM, 105°C overnight),

Figure 1 Overview of rearing conditions and sampling points during the trial. Periods 1–4 cover 0–2745 degree-days post start-feeding (ddPSF). Fish growth expressed as the Thermal Growth Coefficient (TGC) was calculated from bulk weight increase during each period. Black dots indicate intermediate sampling points where 25 fish per tank were weighed and measured. Arrows indicate other events or operations. FW = freshwater; LL = constant light; 12L:12D = light regime used during ‘winter’ stimulation.

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crude protein (Kjeldahl-N×6.25), crude fat (HCl hydrolysis followed by petroleum ether extraction), and ash (550°C 24h). Yttrium was determined in diets and faeces using an atomic absorption spectrometer (Perkin Elmer 3300, Perkin Elmer, Boston, MA, USA) after nitric acid/ hydrochloric acid digestion. Phosphorus and calcium were analysed in diets and faeces by atomic emission spectrometry (ICP-OES) after hydrochloric and nitric acid digestion.

Results During the initial rearing period (Period 1, 0–885 ddPSF), mortality was higher (P<0.001) in fish fed the hydrolyzed fish protein (HFM) diet than in those fed the standard diet (STD), but there were no differences between ploidy groups within diets. The same trend was observed during the entire experiment (0–2745 ddPSF), with cumulative mortality being higher (P<0.001) in fish fed the HFM diet than in those fed the STD diet, but with no significant differences between diploid and triploid fish. There were no clear and consistent effects of either ploidy or diet on the growth trajectories of the fish. During the final study period (1925–2725 ddPSF), there was a significant effect of both ploidy (P = 0.029) and diet (P = 0.010) on the growth of the fish, with triploids fed the STD diet performing better than all other groups. By the end of the

trial (2745 ddPSF) the triploids given the STD diet were both heavier and longer than fish in the other treatments (P<0.001). At this time, however, the diploid fish had higher (P<0.01) condition factors (K) than the triploids. At the parr stage (1390 ddPSF) shortening of the operculum was observed in fish of both ploidies, but no significant treatment effects were seen. At the end of the trial (2745 ddPSF), none of the sampled fish had short opercula (S1 Table) suggesting that recovery may have occurred. At both times, externally detectable jaw or spinal deformities were low (≤2%) irrespective of ploidy and diet and the data were not subjected to detailed statistical analysis. There were significant diet and ploidy effects on vertebral numbers, skeletal deformities and abnormalities. There were slightly, but significantly, fewer vertebrae in triploids (STD diet, 58.74 ± 0.10; HFM diet, 58.68 ± 0.05) than in diploids (STD diet, 58.97 ± 0.14; HFM diet, 58.89 ± 0.01). Triploid fish had a significantly higher (P<0.001) incidence of spinal (vertebral) deformities than the diploids, and vertebral anomalies of four types were recorded. These were type 3 (two-sided compression and reduced intervertebral space), type 5 (one-sided compression), type 6 (compression and fusion), and type 8 (multiple fusion center). Overall, vertebral compressions with or without fusion were equally represented within each diet group. Detailed examination of the triploid fish revealed that the preponderance of deformed vertebrae occurred in the more anterior regions of the spinal column (Regions 1–2; vertebrae 1–30) with vertebra V26 being the most affected in fish fed the STD diet. The incidence of vertebral deformities was lower (P<0.001) in the triploids given the HFM diet than in those fed the STD diet, but was still significantly higher (P<0.001) than in diploids fed either the STD or the HFM diet. Protein ADC was higher (P<0.001) in diploid than in triploid fish for both diets. Digestibility of dietary lipid was unaffected by ploidy or diet but a significant (P<0.001) interaction was observed. Diploid fish fed the hydrolyzed fish protein (HFM) diet had higher fat ADC than those fed the fish meal (STD) diet, whereas the opposite was observed for triploids. Phosphorus ADCs were high (range: 85–89%) with a significant (P<0.01) effect of diet but not ploidy. Phosphorus digestibility was lowest (85%) in triploids fed the STD diet. There were no significant effects of either ploidy, diet or their interaction on calcium digestibility.

Discussion In the present study, mortality did not differ between the diploid and triploid salmon in the period from firstfeeding to completion of the parr-smolt transformation. The mortality observations for the fish given the STD » 17

ARTICLE Figure 2 Lateral view of the head region of fish at parr stage. View of anterior (cranial-trunk) of fish at parr stage (1390 ddPSF). (A) normal operculum and (B) moderate opercular shortening. Scale bars represent 1cm.

diet in the present study resemble those reported in several previous investigations on diploid and triploid salmon, but the mortality regis-

tered for the fish given the HFM diet seems to be higher than the norm. The reason for this is not known but we could speculate that the high

Figure 3 Fish mortality. Percentage of dead fish recorded in diploid (2n) and triploid (3n) salmon fed fish meal (STD) and hydrolyzed fish protein (HFM) diets over (A) the initial period (0–885 ddPSF) and (B) the whole experiment (0–2745 ddPSF). Different letters denote significant differences (P<0.05). Data are presented as mean ± SEM (n = 3).

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early-stage mortality in the fish given the HFM diet was related to poorer water stability and binding in the HFM diet than the STD diet. This could have reduced the availability of feed to the fish given the HFM diet, leading to chronic underfeeding and malnutrition even though the fish appeared to be fed in excess. The triploid salmon had slightly, but significantly, fewer vertebrae than the diploids. In addition, the prevalence of skeletal deformities was higher in the triploid salmon than in the diploids, irrespective of the dietary treatment. As such, these findings are in agreement with those of a number of previous studies on diploid and triploid Atlantic salmon reared in fresh water. There are, however, a number of differences between observations made in the present study and those reported previously. For example, previous studies reported that the highest prevalence of anomalous vertebrae in triploid salmon occurred in the caudal region (V50-V60), whereas the incidence of vertebral abnormalities was highest in the anterior regions of the spinal column in the present study. It has been suggested that a high incidence of vertebral deformities in the caudal region may be linked to dietary phosphorus deficiency. If this is the case it could provide an explanation for the different findings across studies, including the present work. In

our study, all diets contained high concentrations of phosphorus, and bioavailability appeared to be high. Lower temperatures were used in the present study than in several others. High water temperatures during egg incubation, start-feeding and early growth of salmon usually results in increased incidence of deformed fish. Dietary factors, particularly phosphorus concentrations, are also expected to have contributed to the differences in the incidence of skeletal abnormalities observed in various studies. Even though the diets used in the present study had a higher phosphorus concentration (ca. 18 g kg-1) than that previously reported to mitigate vertebral deformities in triploid salmon, the proportions of fish with vertebral anomalies were higher amongst the triploids than diploids. This was the case even though phosphorus bioavailability appeared to be high for fish of both ploidies, irrespective of dietary treatment. The percentage of triploid salmon with vertebral anomalies was lower for those fed the HFM diet than those given the STD diet. Contrary to expectation the inclusion of fish hydrolysate in the diet did not result in any improvement in the ADC of protein for either diploids or triploids. In addition, the ADC of protein in both diets was lower for triploids than diploids, so the inclusion of fish hydrolysate was not effective in alleviating the differences in protein bioavailability observed in the fish fed the STD diet. There were no clear and consistent differences in growth between the diploid and triploid salmon in the present study, although the condition factor of the triploids was generally lower than that of diploids throughout the trial. In the present study, with the triploid salmon given the STD diet being significantly larger than the corresponding diploids at parr-smolt transformation. Thus, it appears that triploid salmon must be fed a diet that is more phospho-

Figure 4 Fish growth from individual measurements. (A) Body weight, (B) length and (C) condition factor of diploid (2n) and triploid (3n) Atlantic salmon, Salmo salar, fed fish meal (STD) and hydrolyzed fish protein (HFM) diets measured at ten sampling points. Results from statistical comparisons among groups are shown for the last sampling point (2745 ddPSF). Different letters denote significant differences (P<0.05). Data are presented as means Âą SEM (n = 3).

Figure 5 Percentage of short opercula in salmon parr. Percentages of short opercula in diploid (2n) and triploid (3n) Atlantic salmon, Salmo salar, parr (1390 ddPSF) fed fish meal (STD) and hydrolyzed fish protein (HFM) diets. Data are presented as mean Âą SEM (n = 3).

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ARTICLE Figure 6 Percentage of vertebral deformities in salmon smolt detected by radiography. Percentages of fish with spinal (vertebral) deformity among diploid (2n) and triploid (3n) Atlantic salmon, Salmo salar, smolt (2745 ddPSF) fed fish meal (STD) and hydrolyzed fish protein (HFM) diets. Different letters denote significant differences (P<0.05). Data are presented as mean ± SEM (n = 3).

Figure 7 Types of vertebral deformities observed in triploid salmon smolt. Mean prevalence of vertebral deformity types in triploid (3n) Atlantic salmon, Salmo salar, smolt (2745 ddPSF) fed fish meal (STD) and hydrolyzed fish protein (HFM) diets.

Figure 8 Occurrence of deformed vertebrae in triploid salmon smolt. Percentage of deformed vertebrae in different regions (R1-R4) of the spinal column of triploid Atlantic salmon, Salmo salar, smolt (2745 ddPSF) fed fish meal (STD) (solid line) and hydrolyzed fish protein (HFM) (dashed line) diets. R1 = cranial trunk, R2 = caudal trunk, R3 = tail region and R4 = tail fin.

rus-rich than current recommendations for salmon in order to fulfil their growth potential. The results of the present study indicate that the incidence of skeletal deformities is low when juvenile salmon are fed high-protein phosphorus-rich diets in combination with low egg incubation and rearing temperatures. Such an outcome was predicted on the basis of the results of previous work that demonstrate the separate effects that dietary phosphorus concentrations and rearing temperature can have on the development of skeletal abnormalities in juvenile salmon. It was interesting to note that feeding a diet with hydrolysed fish protein (HFM) appeared to give a marked reduction in the incidence of vertebral anomalies in triploid salmon compared with triploids fed the phosphorusrich STD diet that lacked the hydrolysate. Although the use of phosphorus-rich diets may be beneficial for the production and welfare of triploid salmon during the freshwater rearing phase, there are also potential negative consequences of using such diets. These diets will increase both faecal and non-faecal excretion of phosphorus, leading to increased phosphorus concentrations in the effluent. High levels of phosphorus present in the effluent released from fish farms contribute to the eutrophication of recipient freshwater lakes, streams and rivers. Consequently, when phosphorus-rich diets are used for the farming of fish in fresh water, some form of wastewater treatment will be required to recover a high proportion of the phosphorus from the effluent.

* Adapted from: Peruzzi S, Puvanendran V, Riesen G, Seim RR, Hagen Ø, Martínez-Llorens S, et al. (2018) Growth and development of skeletal anomalies in diploid and triploid Atlantic salmon (Salmo salar) fed phosphorus-rich diets with fish meal and hydrolyzed fish protein. PLoS ONE 13(3): e0194340. https://doi.org/10.1371/journal. pone.0194340

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Seeking the perfect oyster shell By: Darien Danielle Mizuta1 & Gary H. Wikfors1

Current trends in seafood markets indicate increased demand for within-shell oysters, associated with increased popularity of oyster bars. As this specialized, demanding market increases globally, there is strong incentive to improve quality.


s oysters are displayed in natura, it is no surprise that the appearance of the oyster shell has attained importance and is a high standard in the market. Shell traits can play an important role in product quality control, and consequently commercial competitiveness and demand. As gourmet food, the appearance and presentation of an oyster on the half shell matters as much as taste itself. Thus, shellfish farmers seeking to offer a premium product can take advantage of oyster shell enhancement strategies.

A â&#x20AC;&#x153;good oysterâ&#x20AC;?, based upon shell traits This approach is particularly true for the cupped oysters in the Genus Crassostrea, which account for most of the oysters in aquaculture production. The requirements for a perfect shell include cleanliness, robustness, the right shape, which is based upon measurements of length, width and depth (Figure 1), and might go as far as the right color. Those shell traits are defined by genetics, the environment in which the oysters are grown, husbandry practices adopted in oyster farming, and interac22 Âť

tions among those (Figure 2). Locally, farmers might already have knowledge of, for example, effective farming practices, but local knowledge very often is not disseminated or validated by scientific analysis. Summarizing the current knowledge on the subject is, therefore, both challenging and important. Farmers can have different strategies to classify oysters. In Australia, during the several management steps throughout the grow-out period, Pacific oysters (Crassostrea gigas) are sorted according to shape and returned to

a specific gear or submitted to additional steps in farming management to achieve the perfect shape, defined as a ratio of 3Length:2Width:1Depth. Meanwhile, in Canada, classification of Eastern oyster (Crassostrea virginica) quality based upon shell size and shape is performed after harvesting, therefore better shaped oysters are sold as different categorized products. Most bivalve quality selection is performed manually, although automated graders have been developed, but standardized values for calibration within the market still are lacking.

Image 1. Oyster baskets for tumbling in an intertidal area. Authorized use of photograph from Seapa Company.

Factors influencing shell traits We briefly discuss genetics, environment, and husbandry in relation to shell quality and related industry strategies. Genetics Because a major part of the global shellfish farming industry is dependent upon hatchery produced seed, selective breeding is seen as a means to improve many aspects of crop quality. Breeding goals and genetic selection are based upon economically

important traits. Among the pursued traits in breeding programs are faster growth, lower mortality, and also shell characteristics such as uniformity, color or patterns, and concavity or shell width index (width/length). Each of these characteristics has a different heritability index -- the portion of the phenotypic variance that is of additive nature. Specific traits vary with species and strains, and are further affected by conditions of culture. In fact, selected shell traits may be offset by husbandry, and not revealed in the offspring,

which is reportedly the case if stocking density is too high. The trade-off of decreased stocking, however, may be balanced by the higher price obtained for the premium product. Another common tool used to improve oyster quality is genetic manipulation of ploidy. The use of triploid oysters, which have three chromosome sets and are considerably less fertile than the normal diploids, has also demonstrated shell improvement in cup ratios.

Environmental conditions As shellfish farming is performed in the natural environment, it is not surprising that the environment would have effects upon growing bivalves. Even within a single farm, intra-site variability is commonly reported. Mainly, the hydrological characteristics of the site and depth chosen, which is also dependent upon the rearing method, will determine the shape and thickness of the shell. For instance, in subtidal sites and suspension culture, oysters are constantly submerged and can take advantage of constant food availability; however, fast growth often results in fragile and friable shells. In contrast, Portuguese oysters Âť 23


The use of triploid oysters,

which have three chromosome sets and are considerably less fertile than the normal diploids, has also demonstrated shell improvement in cup ratios.

(Crassostrea angulata) living on the seafloor position the mantle differently depending upon the sediment and water energy and consequently produce rounder and deeper shells in coarser sediments with pebbles. Intertidal and subtidal culture also provide different shellfish products with respect to shell characteristics. Biofouling, such as sea squirts, sea sponges, barnacles, hydroids, macroalgae, worms, and even other bivalves, can decrease shellfish quality with external and internal scars, blisters, shell deformation, and erosion. Such damage hinders commercialization because of unsightly shell appearance. The problem varies depending upon the site and the applied (or lack of) management control, such as baths

of freshwater or appropriate farming equipment to control the biofouling burden. Recent studies show the influence of predator presence can cause juvenile oysters to change shell characteristics, allocating more energy to shell growth and thickening than in locations without predators. This adaptation increases mechanical resistance of shells.

Husbandry practices In a hurry to supply the shellfish market, farmers usually favor culture practices that result in fast shellfish growth to the detriment of shell shape and price in the shelled market. Disseminating knowledge on oyster characteristics in relation to culture practice

Figure 3. Floating bags for tumbling in vertical position during low tide. Bags would horizontally float during high tide. Authorized use of photograph from the Taylor Shellfish Farms Company. Photograph credit: Kristian Marsden.

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is essential to give the producer the choice of making informed decisions on the most suitable method according to the desired final product. The most essential way to obtain shaped oysters is the use of single seed, either obtained from nature or, most commonly, from hatcheries. If oysters are not individually sorted, the oysters grow in clutches, control of shape is impossible, and the shucked market is the most common route of distribution as is common in Japan. Another option is production using single seed in cages, which together with the right stocking density, allow space for oysters to grow with free movement inside the growing apparatus allowing constant trimming of the shell, results in better shaped and cleaner oysters. A widespread management tool that is indispensable for a good shell is tumbling. Tumbling consists of rolling oysters to and fro to break the shell extremities -- a process that thickens shells, make them more cupped, helps clean the shell exterior, and reportedly increases glycogen storage. Tumbling can be performed several times through the grow-out phase, using machine tumbling that requires the harvest of shellfish from the water, or tide or wave tumbling in the intertidal or subtidal environment, taking advantage of innovative culture apparatus such as floating bags (Figure 3) or commercial plastic baskets that allow free lateral movement and constant shaking of shells (Image 1).

Conclusions Aquaculture production has been increasing exponentially in the last decades, and as demand and competition increase, the quality levels are raised. Aggregation of value is considered a good commercial strategy to improve a company’s competitiveness. With the ascension of the within-shell oyster market, good shell appearance is an additional attribute defining oyster quality and is currently commanding higher prices. Poor shell quality may result in unsuccessful attempts by farmers to enter demanding or international seafood markets. Although farming of a ‘good shaped oyster’ imposes additional management efforts and longer grow-out periods the gains in product quality and price suggests advantageous trade-offs. For the complete scientific assessment and technical details please refer to the original publication. 1 Northeast Fisheries Science Center, NOAA, Milford, CT, US. Adapted from: Mizuta, D.D. and G.H. Wikfors. 2018. Seeking the perfect oyster shell: a brief review of the current Knowledge. Reviews in Aquaculture, doi.org/10.1111/raq/12247/

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Corn gluten meal

induces enteritis and decreases intestinal immunity and antioxidant capacity in turbot (Scophthalmus maximus) at high supplementation levels Corn gluten meal (CGM) is an important alternative protein source in aquafeed production. In turbot (Scophthalmus maximus), CGM is not effectively utilized, the reason for which is still unclear. The present By: Nan Bai, Min Gu , Mingjie Liu, Qian Jia, Shihui Pan, Zhiyu Zhang

study investigates and elucidates causes for the poor utilization of CGM by turbot from the view of gut health.


quafeed production is rapidly increasing with the high-speed expansion of aquaculture. Hence, the growth of the aquafeed industry requires sustainable feed ingredients, especially of protein sources. The unbalance between the fish meal supply and demand has stimulated the exploration of alternative protein sources for aquaculture, and research on fish meal substitution has been an international priority for more than two decades. Corn gluten meal (CGM) is the major protein portion obtained from the wet milling process for the separation of the starch, germ, protein, and fiber components from corn. Compared with other vegetable protein sources, CGM is considered a cost-effective alternative protein source for aquafeed owing to its high content of available protein (60%â&#x20AC;&#x201C;70% of the dry matter), low content of fiber and anti-nutritional factors, competitive price, and steady supply. In some carnivorous fish, such as cobia, Japanese seabass, and sea bream, CGM has been shown to successfully replace more than half of the fish meal protein used in the diet without any negative effect on growth performance. However, CGM could not be effectively utilized by turbot, which is considered the most important cultured flatfish in Europe and Asia with

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a global production of around 70,000 t per year. Low digestibility is the key factor limiting the utilization of CGM by turbot, but the causes have been unclear. It has earlier been established that plant protein supplemented in the diet impairs the intestinal health status in several carnivorous fish species, accompanied with poor nutrient digestibility. Our previous work also revealed that dietary soybean meal induced intestinal enteritis and reduced the digestive and

absorptive functions in turbot. Nevertheless, it has been unclear whether the low digestibility of CGM in turbot is caused by the influence of CGM on the intestinal health status, and few reports are available on this subject. We evaluated the effects of CGM on the growth performance, nutrient digestibility, and intestinal health status of this species, determined though assessment of indicators including intestinal morphology, inflammatory responses, immunity, and redox homeostasis.

Materials and methods The protocol for animal care and handling used in this study was approved by the Animal Experimental Ethics Inspection of Shandong University (Permit Number: 20170313). Before sacrificing and handling, experimental fish were anesthetized with 100 ng/ml MS222 (Sigma, USA) and all efforts were made to minimize uneasiness of animals during all processes. Based on previous work, a fish meal based diet (FM diet) was formulated to contain 48% crude protein and 12% crude lipid with fish meal as the primary protein source, fish oil and soybean oil as lipid sources, and wheat flour as the carbohydrate source. This diet was utilized as the control diet. Based on the FM diet, another three isonitrogenous and isolipidic diets were formulated to contain 212 g kg–1, 318 g kg–1, and 426 g kg–1 CGM as replacement of 33%, 50%, and 67% fish meal protein in the basal diet, which were named CGM20, CGM30, and CGM40, respectively. Crystalline amino acids (lysine, argi-

Electron microscopic structure of the distal intestine epithelium. (A) and (C), FM diet, a basal diet; (B) and (D), CGM40 diet. Samples in figure (B) had shorter and less dense microvilli. The white arrow in (A) and (B) represents apical tight junction (TJ). The black arrow in (C) and (D) represents the infiltrated leucocytes from the submucosa into the epithelium layer.

nine, and tryptophan) were supplemented to meet the essential amino acid requirements of turbot or maintain the tryptophan level in the diets.

Apparent disease-free juvenile turbot were obtained from a commercial farm in Haiyang, China, and transferred to an indoor flow-through water system in the Haiyang Yellow

Histomorphological images of hematoxylin and eosin-stained sections of the distal intestine of turbot fed the FM (a, e, and i), CGM20 (b, f, and g), CGM30 (c, g, and k) and CGM40 (d, h, and l).

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ARTICLE Diet Amino Acid Profiles.

Sea Aquatic Product Co., Ltd (Yantai, China). The fish were acclimated to the system and fed the FM diet for two weeks. Next, turbot individuals with an initial body weight of approximately 11.4 g were randomly distributed and transferred into 12 tanks, 30 fish per tank. Each tank was filled Regression analysis of CGM effects.

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with 300 L of seawater. The seawater was pumped from the adjacent coastal water, filtered through a sand filter, and distributed to each tank at a rate of approximately 2.0 L/min. Each diet was fed to fish in three tanks. Fish were fed the experimental diets twice daily (at 07:00 and 18:00) to appar-

ent satiation, and the feed consumption was recorded. During the 8-week feeding trial, the water temperature was 12°C–16°C, pH was 7.8–8.2, and the salinity was 28–30 ‰. After eight weeks of feeding, feces were collected following methods commonly applied for turbot digest-

Microvillar morphology with different diets.

ibility determination. The feces were siphoned with an automatic feces collector 2–4 h after feeding. The pooled feces samples within each replicate were dried for 12 h at 50°C and stored at -20°C. The dry matter, crude protein, and Y2O3 contents of the feces samples were determined. After a sufficient number feces samples (more than 5 g, dry matter) were collected, all experimental fish were anesthetized with eugenol (1: 10,000, Shanghai Reagent Co., Shanghai, China) and their body weights were recorded before sampling. Then, eight fish from each tank were randomly selected, and blood samples were collected from the caudal vein using heparinized syringes. Plasma samples were obtained by centrifugation (4,000 × g for 10 min) at 4°C and immediately stored at -80°C until analysis. Subsequently, the fish were killed with a blow to the head, and their body lengths were determined. The intestine was removed, and only fish with food in the process of digestion in the intestinal tract were sampled to ensure recent intestinal exposure to the diets. Four of the eight sampled fish were randomly selected, and their distal intestines (DI) were removed individually and divided into three parts for histological and gene expression examination. For enzyme activity assessment, the intestinal tissues sampled from the mid-intestine (MI) to DI from the other four fish per tank were frozen in liquid N2 and stored at -80°C. The activities of three brush-border enzymes, including maltase (MAL), leucine aminopeptidase (LAP), and alkaline phosphatase (AKP), four antioxidant enzyme, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxi-

dase (GPX), and glutathione reductase (GR), and lysozyme (LZM), as well as the concentrations of complement 3 (C3), complement 4 (C4), immunoglobulin M (IgM), and the intestinal reduced glutathione (GSH), were subsequently assayed. Intestinal malondialdehyde (MDA) level as lipid peroxidation indication and intestinal acid phosphatase (ACP) activity were also determined. The specific growth rate (SGR) was calculated using the tank means for initial body weight (IBW) and final body weight (FBW), and calculated as follows: SGR = [(ln FBW – ln IBW)/ number of days] × 100. Feed efficiency ratio was calculated as: Feed efficiency ratio (FER) = (FBW – IBW) / total amount of the feed consumed. The apparent digestibility coefficients for dry matters (ADCd) were calculated as follows: ADCd (100%) = (1(Y2O3 % in diet)/ (Y2O3 % in feces)) ×100%. The apparent digestibility coefficients for protein (ADCp) were calculated as follows: ADCp (100%) = (1-( Y2O3 % in diet)/ ( Y2O3 % in feces)) ×(%protein in feces /%protein in diet) ×100%.

Results During the feeding trial no mortality was recorded. Regression analysis results showed a significant inverse relationship between growth and CGM level, following a second-degree relationship. The increased level of CGM reduced those of FER, ADCd, and ADCp following a first-degree relationship. The increase in the dietary CGM levels significantly decreased the specific activities of all the three tested brush-border membrane enzymes. The relationship followed a second-degree function in MAL » 29

and AKP activities and a first-degree function in LAP activity. The inclusion level of corn gluten meal affected all characteristics assessed and induced alterations typical for mucosal inflammation. The severity increased with rise in the level of CGM inclusion. The inclusion of CGM decreased the height and elevated the fusion of the mucosal folds. It also increased the width and cellular (leucocyte) infiltration of the lamina propria and submucosa and reduced the numbers of supra-nuclear absorptive vacuoles in enterocytes. Dietary CGM considerably changed the structure of the distal intestinal microvilli.

ARTICLE Relationships between CGM and various parameters.

The fish fed the CGM40 diet showed significantly shorter and less dense microvilli than those fed the FM diet. TEM analysis results showed that all 12 fish individuals fed the CGM40 diet exhibited higher infiltration of leucocytes from the submucosa to the epithelium layer than that in the fish fed the control diet. Increasing levels of CGM caused no significant difference in serum DAO activity or D-lactate level. In30 »

testinal oxidant indices of MDA significantly increased with the rise in the level of CGM, and the antioxidant indices of SOD, CAT, GPX, and GR activities and the GSH level showed the opposite changes after the CGM inclusion. The intestinal ACP activity, C3 and C4 levels, and IgM level significantly decreased with the increasing level of CGM, but no significant difference in LZM activity was observed with the rise in the level of CGM.

Gene expression levels of Il-1β, Il-8, Tnf-α, and Tgf-β in distal intestinal cytokines showed gradual and accelerating increases with the rise in the CGM level in the diet.

Discussion The findings of the present work showed that the replacement of fish meal with CGM negatively influenced the growth performance, nutrient digestibility, and feed utilization in tur-

Experimental diet composition.

bot. The present study results clearly demonstrated that dietary CGM caused a dose-dependent increase in the severity of inflammatory changes in DI tissue in turbot. Dietary CGM increased the width and cellular infiltration in lamina propria and submucosa, and induced higher expression of pro-inflammatory cytokine genes, including Il-1β, Il-8, and Tnf-ι. Intestinal immunity and redox homeostasis play pivotal roles in maintaining intestinal health in fish. The intestines of teleosts have various important defense molecules, such as lysozymes, complement systems, phosphatases, and immunoglobulins, which participate in protection against microbial pathogens. In the present study, we observed negative effects of CGM on the intestinal immunity of CGM-fed fish revealed by the decreased activities

of ACP and the C3, C4, and IgM levels in a dose-dependent manner, which is similar to the impairment caused by a soybean meal on the immune system in several finfish species. The fish intestine has high content of polyunsaturated fatty acids (up to 24.9% of the total fatty acid composition), which increases its susceptibility to the negative effects of reactive oxygen species. The imbalance in the redox homeostasis in the fish intestine results in considerable lipid peroxidation, expressed by the increased MDA content. In the present work, the intestinal level of MDA increased with the rise in the CGM level, suggesting that CGM supplementation induces intestinal oxidative injury in turbot. In the present work, antioxidant parameters decreased with increases in CGM inclusion.

In conclusion, CGM exerted negative effects on the intestinal health in turbot, including the induction of enteritis in the DI tissue and impaired intestinal immune and antioxidative systems. CGM may induce enteritis in a way that is different from that of soybean meal since the cellular tight junction structure and the intestinal permeability were not affected by its inclusion. The present work directly suggests that strategies to maintain intestinal health should be developed and undertaken when formulating turbot diets containing CGM. The authors work at the Marine College, Shandong University at Weihai, Weihai, Shandong Province, PR China. This article was adapted from: Bai N, Gu M, Liu M, Jia Q, Pan S, Zhang Z (2019) Corn gluten meal induces enteritis and decreases intestinal immunity and antioxidant capacity in turbot (Scophthalmus maximus) at high supplementation levels. PLoS ONE 14(3): e0213867. https://doi. org/10.1371/journal.pone.0213867

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Countries and Experts Commit

to Collaborate for the Sustainable Evolution of the Aquaculture Sector By: World Organization for Animal Health (OIE) *

In early April, the World Organization for Animal Health (OIE) hosted international experts in aquatic animal health from the private and public sectors to discuss the seafood revolution and how they can collaborate to overcome its challenges and support its growth in a sustainable way.

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ore than 250 people representing 90 countries participated in the OIE Global Conference on Aquatic Animal Health, which was held in Santiago, Chile, April 2-4 2019. The event highlighted the multiple opportunities for continued growth that the aquaculture sector has available to it and the need for collaboration between decision-makers, aquatic animal health professionals, and other partners for assuring its safe and sustainable development. ‘The world has a big challenge forward in terms of animal proteins,’ said Jose Ramon Valente, Chilean Minister of Economy, Development and Tourism. ‘The 7 billion people that we are today, and that will become 9 billion by 2050, have a tremendously increased demand for calories and, especially, for proteins. This conference will help us to understand what are the conditions that must exist in the world to encourage food production in a way that is compatible with the environment and sanitary standards.’ Aquaculture is a recent industry, growing at about 6% per year. In 2014, it achieved the remarkable milestone of surpassing fisheries production. Projected seafood demand is strong due to the rising middle class and new dietary recommendations, but aquatic animal diseases threaten to limit its production and growth. ‘Unfortunately, the rise of aquatic animal production, particularly through intensification of aquaculture and trade presents serious challenges’ pointed out Dr. Mark Schipp, President of the OIE World Assembly of Delegates. ‘These include increased local, regional and global exposure to the risk of disease emergence and spread. Protecting our valuable aquaculture and fisheries commodities, and the environment that supports them, requires rapid advancement and implementation of management practices to combat this risk. The transnational spread of

aquatic animal diseases is a serious issue that has devastated aquatic animal production in many countries, and the OIE standards aim to reduce these risks substantially.’ To be able to feed the world tomorrow, the aquaculture sector also needs to face and overcome significant day-to-day challenges. ‘Our sustainability journey is just beginning,’ said George Chamberlain from Global Aquaculture Alliance. ‘When you look at climate change, social issues, plastics in the oceans, antimicrobial resistance, feed ingredients, there is a tremendous amount of work to be done. Collaboration among us is the key going forward.’ During the three-day event, participants had the unique opportunity to discuss improved approaches to emerging disease response, best biosecurity practices, strategies to reduce the use of antimicrobial agents, and

‘The world has a big challenge forward in terms of animal proteins,’ said Jose Ramon Valente, Chilean Minister of Economy, Development and Tourism.

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Projected seafood demand is strong due to the rising middle class and new dietary recommendations, but aquatic animal diseases threaten to limit its production and growth.

the importance of implementing the OIE international Standards. A series of bold recommendations were released at the end of the meeting that will be submitted to the OIE World Assembly in May 2019, for endorsement. 34 »

These recommendations notably urge the Members to: • Take steps to improve compliance with the OIE Standards, notably surveillance and early detection; notification to the OIE of aquatic animal diseases; and the prevention and con-

trol of pathogenic agents in aquatic animals • Implement biosecurity measures to mitigate the risk of the introduction or release from the aquaculture establishment • Ensure transparent, timely and con-

sistent notification of all OIE listed disease and emerging disease to the OIE through WAHIS to support other Countries in taking appropriate action to prevent the trans-boundary spread of important diseases of aquatic animals • Ensure that the OIE Standards and guidelines for responsible and prudent use of antimicrobial agents are respected at the country level and

To be able to feed the world tomorrow, the aquaculture sector also needs to face and

promote advances in disease management to reduce the need for antimicrobials ‘On the basis of these recommendations, let’s try to build a project together combining all partners’ initiatives to find synergies and maximize the impact on the results. ‘This is the challenge of the OIE for the coming years’, said Dr. Monique Eloit, OIE Director General. Collaboration, sustainability: our future—the focus of this year’s conference is a timely one. By working together and investing in aquaculture today, we can ensure the sustainable evolution of the aquatic animal production and safeguard our future. The OIE would like to thank the Government of Chile for its significant support in organizing this conference.

overcome significant day-to-day challenges. OIE staff.

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Local Food Systems and Market Opportunities for Aquaculture Products

Using information gathered from 10 food hubs and commercial kitchens in Indiana and Illinois, we evaluate the prospects of marketing By: Akua S. Akuffo (PhD) and Kwamena K. Quagrainie (PhD)


ocal food systems are growing, attracting continued interest by consumers, producers, and policymakers. Federal, state, and local governments as well as communities have developed policies relating to the production and/or processing of foods at various points of sale and/ or consumption. The attention on local foods at the federal level has buttressed the local food movement and the establishment of local food systems, and enabled states, counties and municipalities to adopt food policies to increase the local economic activity around farming and foods consumption. Over half of the states in the U.S. have a statewide food-policy council. Local food systems include food supplied through direct-to-consumer channels (e.g., on-farm stores, and Community Supported Agricultural CSA arrangements, farmersâ&#x20AC;&#x2122; markets, roadside stands) and through intermediary marketing channels (e.g., supply to restaurants, grocery stores, institutions and/or to regional food aggregators such as food hubs, and cooperatives). Food aggregators respond to the distribution challenge for retail buyers of local foods: 58% of food hubs sell to restaurants, caterers or bakeries, 39% sell to small grocers, and 35% sell to K-12 food service. Most regional food hubs handle traditional agriculture products such 36 Âť

aquaculture products through these businesses.

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as fresh produce and livestock products, however no seafood. This suggests that the seafood industry, and the aquaculture industry, may be missing an important marketing outlet for aquaculture products. One of the main purposes of a food hub (regional food aggregator) is to provide local producers with access to larger volume local markets as an alternative to direct-to-consumer marketing options. Food hubs actively coordinate supply chain activities, seek new markets for producers, and build strategic partnerships with processors and other distributors so that members can meet the quality and quantity requirements demanded by local commercial and institutional buyers. Farmers and ranchers who utilize food hubs benefit from the distribution and processing infrastructure of appropriate scale, which gives them wider access to local retail, institutional, and commercial foodservice markets, where demand for local and regional foods continues to rise. This study examines the prospects of marketing aquaculture products through food hubs in the Great Lakes region. The addition of aquaculture products in food hubs could translate into the expansion of aquaculture produc-

tion. However, processing has been one of the major challenges for aquaculture producers, mainly small- and medium-scale because of limited processing capacity in the region. To fully utilize the local food system, it is imperative that the aquaculture industry explores local processing services such as shared-use and commercial kitchens. Aquaculture producers can benefit from food hubs’ services that actively find partners to provide post-harvest assistance. Some traditional food hubs offer processing services for their clients using facilities that have the necessary equipment, infrastructure, and food safety requirements to develop and market value-added products. Progressive food hubs can assist producers in production planning, sustainable production practices, food safety, and post-harvest handling to increase the capacity of producers to meet local wholesale and retail buyer requirements such as quality, volume, consistency, packaging, liability, and food safety. Given such linkages, demand for a wide range of locally sourced aquaculture products currently being grown or capable of being grown could increase significantly.

Figure 1 Types of Business Registrations for Food Hubs. Non-profit


For Profit

50% 17%


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One of the main purposes of a food hub (regional food aggregator) is to provide local producers with access to larger volume local markets as an alternative to direct-toconsumer marketing options. Seafood Production in the Midwest Seafood production is limited in the Midwest, contributing less than 1 percent of seafood farmed and consumed in the U.S. The Illinois Department of Natural Resources (DNR), reports about 70 licensed freshwater aquaculture facilities, with most facilities farming native species that are raised indoors, and in lakes and ponds. The Indiana DNR reports 29 aquaculture permit holders, while Ohio’s DNR reports about 28 facilities (fish propagators). Examples of food species produced in these states include largemouth bass, bluegill, rainbow trout, hybrid striped bass, yellow perch, tilapia, barramundi, channel catfish, and freshwater and saltwater shrimp. Data and Methodology We conducted a survey of select food hubs and shared-use kitchens in two states – Illinois and Indiana, with emphasis on the quality of information derived. The survey asked questions about location; business registration (i.e. non-profit, for profit, cooperative, community or public owned, other types of business registrations); years of operation; number of employees and producers/tenants; the array of products handled; annual sales; rent charges and the constraints facing market entry for producers. Additional questions related to seafood handling; interest and willingness of operators to handle seafood; availability of logistics; and types and forms they can accommodate in their facilities.

The addition of aquaculture products in food hubs could

translate into the expansion of aquaculture production.

Food Hubs – Through the online survey, we collected operational and financial information from selected food hubs. More specifically, the survey inquired about the type of business registration, the number and location of outlets they operate, the size of labor and, types of produce they handle, revenues and logistics available to accommodate seafood in the future. Follow-up phone calls and visits were made to certain food hubs for additional information on food safety regulations and cost of certifications for their producers, particularly those involved in processing and seafood. Shared-Use & Commercial Kitchens – First, we assessed the requirements for new users / tenants; capital requirements, licensing, certifications, etc., and examined the various uses of the facility. We also asked owners / operators of shared-use kitchens if they have additional resources to help tenants, such as instructions and consulting services relating to business planning, product development, branding, etc. We examined payment arrangements by tenants. Published reports indicate that these kitchens mainly have rental agreements. Some questions related to what factors affect rental rates. Are they fixed, or do they vary with frequency of usage, usage over a period, volume of activities, etc.? How competitive are rents in » 39

ARTICLE Figure 2 Cost Allocations for a Cooperative Food Hub.

Cost Allocations

Bank / credit card charges

Food hubs also obtain

funding from contracts Operations of the food hub

between them and organizations like hospitals, educational institutions, and restaurants.

Farmers 0%








80% 90%

Percentages of cost allocations

comparison to market rates, and how often do they change over time?

Results and Discussion The response rate for the questionnaire was 31.3% (10 out of 32). There were 3 responses from Illinois and 7 from Indiana. We interacted face to face and by phone with two food hub operators to garner more information about costs and food safety regulations. We also interacted with the community manager of a commercial kitchen about their operations. Business Model and Operations Food hubs, like any business, are not only concerned with making profit, but also with being productive and competitive. The common business models for food hubs are non-profit, cooperative and for profit (Figure 1). On average, the surveyed food hubs have been operating for 5.5 years, with some co-ops being in operation for as long as 20 years. Except for one food hub, which has a meat processing facility, all other food hubs only aggregated and distributed. Irrespective of the type of business model, a contract or membership agreement is required between the food hub and the producer. Most food hubs are funded through government grants like the Specialty Crop Block Grant and the 40 Âť

Local Food Promotion Program. Food hubs also obtain funding from contracts between them and organizations like hospitals, educational institutions, and restaurants. Some food hubs operate daily markets, cafes, and restaurants, from which they obtain additional income.

sentative noted in conversation that, the variety of produce they carry requires the satisfaction of three different regulatory bodies: the Indiana State Department of Health, the Indiana State Egg Board and the Indiana State Board of Animal Health. The Meat & Poultry Inspection Division of the Indiana State Board of Animal Health must further certify food hubs with a processing facility. Producers also need certifications like Good Agricultural Practices (GAP) in dealing with a food hub.

Costs and Revenue Distribution The cost distribution of a food hub operating under a cooperative business model (majority of food hubs) is shown in Figure 2. A single food hub can earn up to approximately USD$ 1.8 million per annum from sales and Product Array other operations. The common commodities carried by the food hubs are fruits and vegetables, meat & dairy, and non-food Labor Labor according to the food hub oper- items. Beverages (alcoholic and nonators is one of the most expensive in- alcoholic) and seafood are least computs. The number of employees from mon items sold by food hubs. About our survey ranged from 2 to 20 paid 40% of our sample handled seafood workers and volunteers, with 3 being in their food hubs. Reasons for this the highest number of paid workers low percentage involved handling reon average. Most of the food hubs de- quirements imposed on producers. pend on volunteers as labor. In one of About 30% of our sample was willthe food hubs, the President/Execu- ing to carry seafood as a product if tive Director, the marketing manager they received proper oversight from and board members are all volunteers. the health department and if there were no extra regulations. However, Health and Food Safety Regula- seafood requires extra regulations because the Food and Drug Administions and Certifications For a food hub to operate in Indiana, tration (FDA) has different protocols they must satisfy certain food safety from the USDA, which regulates all requirements. One food hub repre- meat except seafood.

The outcome of the survey and personal interactions with the various operators of food hubs and commercial kitchens indicated that there are opportunities for local seafood producers in Indiana and Illinois.

Barriers to Market Entry Constraints and problems with respect to market entry and expansion generally fell into three categories: marketing (low retail sales & wholesale networks, low sales force, small-time producers unwilling to allow channel/wholesale price cuts), capital (lack of capital resources) and licensing/ regulations (state zoning regulations, certifications for producers). Other constraints included the inability of some food hubs to carry a wide variety of produce and the lack of a loading dock in some facilities to accommodate food trucks. Commercial and Shared-Used Kitchens There were 3 commercial kitchens in our sample, all for-profit. These kitchens have been in operation for about 3.5 years on average. The commercial kitchens require membership before a tenant can use their facility. In addition to providing processing space for tenants, some kitchens provide additional services like training in kitchen and food safety, entrepreneurship and culinary education, as well as packaging, labeling, pricing and cleaning services after tenants have finished using the kitchen. Commercial kitchens get revenue from membership and rental fees. Labor used in these kitchens are paid and they range between 1 to 3 workers.

Staff within some kitchens include a President, Director, Community Manager, Kitchen Coordinator, Member Success Manager, chefs, etc. Commercial and shared-use kitchens profit from rental fees from tenants. Some pay hourly and others have a monthly subscription fee. Scheduling is mainly online and on a first-come first-served basis. An example of the hourly rate from one of the kitchens in Indiana is $14; it costs more in Illinois. One surveyed kitchen has tenants paying rent monthly in the range of $325 to $1,100. All three kitchens allow the processing of seafood in their facility. One of the kitchens has a special room where gluten-free items are processed. To be operational a commercial kitchen must meet all state and federal requirements. Meat processors must meet USDA/Food Safety Inspection regulations. Even if a kitchen is certified, each tenant must also be certified (e.g. Food Safety manager certificate) to use the facility. Some kitchens also require liability insurance from their tenants. Food processors must also follow good manufacturing practices and have a Hazard Analysis and Critical Control Point (HACCP) plan.

Implications for the Aquaculture Industry Our survey results and interactions with food hub and commercial kitchen operators highlight the following: • For food hubs to commit to processing and marketing locally produced seafood, producers need to meet supply frequency and quantities. Food hubs tend to have contract obligations with their institutional buyers and therefore require consistency in supply from producers. One way for the aquaculture industry to meet this requirement is for producers to consider some form of aggregation to obtain volume and dependability in supply. • Commercial kitchens are a good starting place for small- to mediumscale local seafood producers because of the low cost involved. Most of

these kitchens allow seafood processing and they have storage and other services for value addition. • Commercial kitchens have a diverse group of tenants that utilize the facilities for value-added product development, food business incubators, preparing food for catering, and other food businesses. Some of these tenants are prospective customers for processed aquaculture products. • Seafood producers can acquire food safety certifications from some of the commercial kitchens that offer Food Safety workshops. • Food hubs are continually looking to expand their product array; local seafood producers with food safety certifications should reach out to food hub operators for marketing opportunities.

Conclusion The responses from email and phone conversations with food hub and commercial kitchen operators indicate that: 1) seafood is not a common product carried by food hubs because of the barriers created by licenses and certifications required from both producers and marketing channels operators, and 2) there is a lack of information concerning the costs and benefits of not only aggregating and distributing seafood but also processing available seafood to food hub operators. The outcome of the survey and personal interactions with the various operators of food hubs and commercial kitchens indicated that there are opportunities for local seafood producers in Indiana and Illinois. Some strategic alliances may be required to meet supply frequencies and quantities of food hubs.

We extend our appreciation to Illinois-Indiana Sea Grant for their financial support, to all the operators of the food hubs and commercial kitchens in Indiana and Illinois who responded to our survey and spoke with us on the phone, and to the staff of Purdue Extension and the Food Science Department of Purdue University. Akua S. Akuffo (PhD) and Kwamena K. Quagrainie (PhD) can be reached at the Department of Agricultural Economics, Purdue University, West Lafayette, Indiana. kquagrai@purdue.edu

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Africa Report: Recent News and Events By: Staff / Aquaculture Magazine

Nigerian Government Funds Community Level Training for Aquaculture Development The Acting Executive Director/ Chief Executive Officer of the Nigerian Institute for Oceanography and Marine Research (NIOMR), Dr. Patricia Anyanwu, stated that based on statistics illustrating steady growth, aquaculture is a promising area for investment. Dr. Anyanwu made these comments during a fish value chains training for unemployed youth and women. Such training is currently taking place across the country. “With the recent Statistics of the Federal Department of Fisheries, you will find that fish production is increasing, aquaculture is increasing at a high rate, and this is the outcome of the trainees of the workshops,” Anyanwu said. “The trainees, most of them have diversified into various aquaculture value chain like smoking, hatchery production. One of our trainees is now training others within her community, gathering many women who come together at her farm to learn how to grow fish. That is the multiplier effect of the training program.

“With the starter pack we have given to them, they will expand through economy of scale and begin to make money when they re-invest in the next cycle and, in a way, boosting fish production in the country,” she stated. “Very soon we will be talking about mari-culture, which means we will be raising fish in the sea or not too far from the land, or in cages to raise the fish” added Dr. Oresegun Adekunly, Biotechnology Director and Coordinator of Training for NIOMR.

FAO Validates Gambian Aquaculture Policy Analysis A recent report on Fisheries and Aquaculture Policy was validated by the FAO earlier this month. The review and analysis of the Gambian Government’s policies includes strategies to advance food and nutritional security of the country’s population. A two-day review and validation meeting was organized as a logical continuation of the decision taken by 42 »

the ECOWAS Commission to provide member States with a Regional Fisheries and Aquaculture Policy, to be oriented towards the food and nutritional security of West African populations. Speaking on behalf of the FAO’s representative in the Gambia, Madam Serry Njie Sanyang stated the event constituted an important moment in the cooperation between FAO and the Government of the Gambia, reflecting the dynamism and diversity of this cooperation in all sectors as well as the fisheries and aquaculture contribution to food and nutritional security in the country. “The program impacts on the resilience, sustainability and transformation for food and nutrition security and is a partnership program between FAO and the European Union,” she said. She added that the partnership aims to provide political assistance mechanisms to improve food and nutrition security, while at the same time contributing to the achievement of the FAO’s strategic objectives.

“To achieve our objectives it is important to periodically review the policy and all its strategies and action plans,” said Malang Darboe, the Deputy Permanent Secretary at the Ministry of Fisheries and Water Resources. He added that the Ministry continues to give high priority to the development of Fisheries, because of the role of the sector in economic and social development. He pointed out that the sector provides employment for the youth, while generating revenue and foreign exchange earnings for the Gambian economy. “With the technical and financial support of FAO and the European Union, a regional Fisheries Policy will not only orient the people towards food and nutritional sufficiency, but will sustainably fight against poverty and facilitate the achievement of our strategic objectives,” said Mr. Darboe.

Agritech Expo Zambia Launches Free AgriTEACH Workshop Programme Line-Up AgriTEACH workshops are focused on skills development, aimed at addressing current farming challenges and offer practical, smart and innovative solutions to ensure quality farming and maximum pro-

duction, season after season. Farmers have the opportunity to attend multiple workshop sessions taking place across four different industry themes, allowing a more focused and detailed knowledge- building experience. The sessions cover agricultural sectors such as crops, finance, irrigation, machinery, equipment and livestock. There are also opportunities for farmers to obtain free, professional advice from experts. Some of the leading expert speakers at the AgriTEACH workshops at Agritech Expo Zambia who have shared their experience and latest technology in aquaculture include Sikabalu Malawo, Technical Sales officer, Skretting Zambia. Malawo states, “The aquaculture status in Zambia is rapidly increasing with a number of donorsupported aquaculture development programs targeting small-scale farmers.” David Elias Daka, Animal Production Consultant at Livestock Services Cooperative Society in Zambia added, “Nutrition and feeding account for a major cost of production and farmers will learn how this cost can be reduced.” This year’s event at The GART Research Center in Chisamba was expected to bring more than 20,000

visitors from some 39 countries, over 220 local and international exhibitors, including country pavilions from as far away as Germany, China, Czech Republic, the European Union, Italy and the UK, with 3500 VIP and large scale farmers and 150 members of the media. Last year Agritech Expo Zambia won the AAXO ROAR award for Best Africa Bound Trade & Consumer Exhibition in the 12000+ sqm category at the AAXO ROAR Organizer and Exhibitor Awards in Johannesburg which honor excellence in the exhibition and events industry on the continent. In 2017 the event also won for Best Trade & Consumer Exhibition 12000+ sqm and for Distinction in Social Responsibility. The expo has an outreach program at the local Golden Valley Basic School, where, with the assistance of numerous event sponsors, it is assisting the school with much needed infrastructure upgrades, equipment supplies and management of the school’s farm. Agritech Expo Zambia is owned by the Zambia National Farmers Union (ZNFU) and is organized by Spintelligent, a leading Cape Townbased trade exhibition and conference organizer, and the African office of Clarion Events Ltd., based in the UK. » 43


Latin America Report: Recent News and Events By: Staff / Aquaculture Magazine

Hendrix Genetics and Nutreco collaborate to deliver sustainable shrimp solutions in Ecuador Hendrix Genetics, Nutreco (with aquaculture division Skretting), and Ecuacultivos will invest capital in upgrading the Macrobio hatchery to a state-of-the-art production facility and developing a world-class local shrimp breeding program. The joint venture aims to increase the competitiveness of the Ecuadorian shrimp industry in a sustainable manner. The hatchery is located in the western region of the country and currently employs around 50 people. Antoon van den Berg, CEO of Hendrix Genetics, states “After our entry into shrimp breeding in 2017, we have put most effort into developing the Kona Bay shrimp breeding program. This is an important development to gain access to one of the main markets.” “Our strategy for the coming years is to invest in innovative projects that support sustainable market growth,” explains Nutreco CEO Rob Koremans. “We’re delighted that this partnership will promote the sustainable growth of shrimp farming in Ecuador.” Within the aquaculture market in Ecuador, the Pacific whiteleg shrimp is the most important aquatic species produced. The production volumes skyrocketed in recent years, putting Ecuador currently at the third largest producer after China and Indonesia. The market for Ecuadorian shrimp has also changed drastically. In the past, the European Union and the United States were, by far, the largest 44 »

markets. However, China is now importing about 50% of Ecuador’s total shrimp output.

Regal Springs introduces its Sustainable Mojarra Farming Program “CUIDAMOS” (“We Care”) in México At a press conference in Mexico Regal Springs recently introduced its new initiative “Cuidamos” a first of

its kind sustainable mojarra-farming program that contemplates the process from the harvesting to the final processing stage of the fish. The initiative began in 2018 and it will be running until 2023, a period planned to function as a unification engine for the improvement of the general operation of Regal Spring’s productive chain in Mexico. “Cuidamos” adheres to the UN’s Sustain-

able Development Goals and places this country at the forefront of the market as an ambassador of responsible aquaculture product exports. More information about the project can be found at: https://www.regalsprings.com.mx/cuidamos-azul/ .

New strategic planning introduced for Costa Rican aquaculture Recently, authorities from INCOPESCA (Costa Rican Fishing and Aquaculture Institute) and SEPSA (Executive Secretary of Agricultural Sectorial Planning) officially introduced the Strategic Plan for Costa Rican Aquaculture 2019 – 2023, as a framework for strengthening and developing this nationally important productive activity. This plan is the result of interaction and agreement amongst different key actors of the field with the main goal of improving the aquaculture industry in Costa Rica and its international competitiveness. Shared knowledge and experience in this proposal merge the interests of public servants, private initiatives, the academic sector and of course the country’s fish farmers. Vice minister of Agriculture and Livestock, Bernardo Jaén Hernández stated, “The main purpose of this Strategic Planning is to enhance an organized development, that can be sustainable and environmentally friendly for aquaculture activity, and that is innovating through scientific research and promoting social growth and development on an equitable basis.” Moisés Mug Villanueva, Executive President of INCOPESCA, highlighted the importance of this productive activity for Costa Rica, stating that in 2018 the country produced close to 22 thousand metric tons of farmed species such as tilapia, trout, shrimp, prawns, oysters and snappers. This effort to boost the development of the aquaculture industry in

Costa Rica had technical and financial support from the Food and Agriculture Organization of the United Nations through the preceding study “First Diagnosis of Aquaculture in Costa Rica, 2016,” as well as support and coordination from local governmental and academic institutions.

Mexican initiative #PescaConFuturo (#FishingWithAFuture) is a finalist at the Seafood Champions Awards This initiative from the Mexican Council for Promotion of Fishing and Aquaculture Products (COMEPESCA) has been nominated as a finalist in the fifteenth edition of the Seafood Champions Awards that will be celebrated as part of programmed activities for the SeaWeb Seafood Summit next June in Thailand. The Seafood Champion Awards recognizes individuals and companies for outstanding leadership in promoting environmentally responsible seafood in ways that lead to industry innovation and change. COMEPESCA is building a Mexican sustainable seafood movement. As a multi-stakeholder group comprised of predominantly industry members, it is dedicated to promoting the consumption of Mexican seafood products. The organization designed and implemented #PescaConFuturo (or “fishing with a future”), a first-ofits-kind campaign to promote the

consumption of sustainable Mexican seafood and créate a voice for responsible seafood producers and distributors. The project is competing against three other initiatives in the Seafood Champion Award for Advocacy, which recognizes the promotion of sustainability, use of the media to raise the profile of sustainable seafood, efforts to strengthen public policy and resource allocations, and championing advances in sustainable seafood. This year’s finalists (17 in total for four different awards) represent a diverse cross-section of individuals, governmental organizations, nongovernmental organizations (NGOs) and seafood companies from all corners of the globe. In addition to geographic and industry diversity, the Seafood Champion Awards is committed to elevating under-represented voices and promoting greater gender diversity in the seafood movement. Notably, the women finalists represent an array of accomplishments, including how seafood is produced, processed, sold and consumed. More information about this event honoring those in the seafood industry whose past and/or present contributions demonstrate commitment to innovations that lead to change can be accessed at: https:// www.seafoodsummit.org/seafoodchampions/.

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Fish Feed Labels By: Álvaro García

Fish feed tags or labels are used to register, identify, and market a complete feed or “ration.” In reality, the tag is also a legal binding document by which the feed manufacturing company guarantees the product contains the ingredients declared, as well as certain concentrations of “key” nutrients.


he Food and Drug Administration (FDA), in cooperation with state and local partners, is responsible for the regulation of fish feeds. Working with the Association of American Feed Control Officials (AAFCO) and the States, the FDA implements policies to regulate fish feed products. Part of this cooperation entails creating feed ingredient definitions as well as establish maximum and minimum safe nutrient concentrations suggested for feed ingredients and finished feeds, to assure fish perform satisfactorily in accordance with their different productive stages. While the FDA regulates the use of feed ingredients and complete feeds, it is up to feed manufacturers to make sure their products comply with these regulations before they enter the food chain. Adequate feed labeling, then, is not only a requisite for commercialization but also serves as a guideline for the fish farmer. The fish performance expected with a certain feed is a function of: 1. The feed manufacturer (e.g.) type and quality of ingredients and their processes 2. The fish farm: (e.g.) adequate feed storage and feeding for its intended purpose

The feed tag Fish feed tags or labels are used to register, identify, and market a complete feed or “ration.” In reality, the tag is also a legal binding document by which the feed manufacturing company guarantees the product contains the ingredients declared, as well as certain concentrations of “key” nutrients. The fish farmer can then make a more informed decision of which type/brand of fish feed to buy based on the growth stage for a particular species, ingredients, maximum and minimum concentrations of essential nutrients, and - very importantly - price! Reducing feed costs positively impacts fish farming; however, it is also the goal of the feed manufacturers 46 »

When selecting a fish feed one has to consider the nutrient needs of the species being fed, the quality of its ingredients, the adequacy of its processing, and ultimately the feed price. that supply the feed. With feed costs in fish farms usually above 50% of total costs of production, it is critical for the farmer to select a feed with an optimum compromise between price and quality that will not hamper fish performance. Adequate fish feed quality also results in less waste, helping maintain water cleanliness, and reducing negative impacts on fish health and the environment. Feedbags, or any other containers, come with a label from the manufacturer. Some bags have a stitched paper label, some have it printed on the side, and some have both. The label has the information required by federal regulations from the FDA, in coordination with the Center for Veterinary Medicine (CVM), following guidelines from the AAFCO. Feed labels must show the name and address of the manufacturer, a description of the contents (ingredients and key nutrient concentrations), date of processing, and guidelines for the feed’s use for a certain species and productive purpose (e.g. starter, growth, finishing). Fish feeds have different presentations (e.g. crumbs, pellets, flakes) and properties (e.g. floating, sinking) suited for different fish species and/or growth stages. Within each presentation, particle size must be in accordance with the preference of the growth stage of the fish to be fed. When selecting a fish feed one has to consider the nutrient needs of the species being fed, the qual-

ity of its ingredients, the adequacy of its processing, and ultimately the feed price, in that particular order! Since feed costs represent in excess of 50% of the cost of production it is very tempting to reverse the order and choose first based on low price. As mentioned above, feed mills also need to make ends meet. And regrettably, there is “no magic” in feed formulation, and economies of scale aside, a lower price is in general not associated with higher quality or choice ingredients. Having said this, the opposite does not always hold true either; a more expensive feed does not guarantee higher quality. An almost “fool proof ” method to guarantee quality is to measure fish performance; how well did fish do when fed ration “x”? It can be personal experience or that of another fishery, better yet a soundly

designed feed trial conducted by the manufacturer in cooperation with a well-known research institution. This is how well known feed manufacturers usually build their reputations. There are a few key components that determine fish performance. Some are associated with the formulation of the diet, and some with the processing methods in the feed mill. First, fish feeds should be balanced by a knowledgeable fish nutritionist, who takes good care of making sure all nutrients the fish need are present in the finished product. However, it is difficult to learn this from the feed tag exemplified here (Fig. 1); we only know which feed ingredients are included but not in what proportions. Again, we need to rely on the reputation of the manufacturer and the expertise of its nutri-

Fig 1. Example of a feed label.

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Good quality fish meal is

highly palatable, has excellent nutritional properties such as high protein digestibility and contains most essential amino acids in the concentrations fish require.

48 Âť

tion consultant(s). The same applies to how well the fish will eat this feed (palatability). Fish fed two different complete feeds with the same ingredients can perform differently, depending on the proportions of each ingredient, their amino acid balance, and palatability. There are limitations to how much of each ingredient fish will tolerate in a feed without having negative impacts on acceptance. This is also something a highly skilled nutritionist should be aware of, and formulate accordingly. Finally, and further complicating this issue is the presentation of the feed, such as for example pellets or flakes and their size, as well as their density.

Let us look again at the feed label above and analyze it item-by-item (Fig 1).

Protein This feed tag declares a minimum of 45% crude protein. Because of the high cost of the ingredients that supply protein to fish diets, one can rest assured that if practically possible, this ration would contain exactly 45.000% crude protein or even 44.999%! There will always, however, be a â&#x20AC;&#x153;safety marginâ&#x20AC;? for the feed mill (included to assure compliance), and the diet will likely be formulated to contain 1-2% units of crude protein above 45% (4647%). Regrettably, the amount does

(digestibility) of the other animal proteins included in this ration will be highly dependent on aspects of their processing, such as drying temperatures (affects all), the processes used (hydrolyzed Feather Meal) or the inclusion of different animal parts (Poultry By-Product Meal). How much Fish Meal, Poultry By-Product Meal, Blood Meal, and Feather Meal are included depends on the amounts necessary to formulate according to the requirements of the particular fish species and the price/availability of each feedstuff. Table 1 shows likely concentrations of protein, fat, fiber, and ash of the ingredients declared in this feed tag. Because of their predatory nature salmonids require high protein and high energy diets. Animal protein concentrates are usually ingredients of choice to formulate their feeds because of their excellent amino acid balance as well as energy content. Plant protein concentrates (e.g. soybean, distillers dried grains, etc.) can still be used to successfully formulate diets, although there are claims that their palatability is lower. Good quality fishmeal is highly palatable, has excellent nutritional properties such as high protein digestibility and contains most essential amino acids in the concentrations fish require. Rendered animal proteins such as Poultry By-Product Meal are also sought as a more economical Fish

Regrettably, the amount does not tell us anything about the quality of a protein, which is determined by the balance of its essential amino acids â&#x20AC;Ś Again we depend on the nutritionist and the formula used in this instance. not tell us anything about the quality of a protein, which is determined by the balance of its essential amino acids. What we do know from the ingredients listed is that the amino acid profile will be a combination of the proteins in Fish Meal, Poultry By-Product Meal, Blood Meal, Feather Meal, Whole Wheat, and DL Methionine (an often-deficient amino acid). Again we depend on the nutritionist and the formula used in this instance. As strange as it may sound, the best amino acid profile in a single protein fed to a given animal species is the protein present in the tissues of that same species or even related ones. Fish is no exception, and the best amino acid balance in protein concentrates is that found in Fish Meal. The amino acid availability

Meal replacement. Poultry By-Product Meal is nowadays considered in the formulation of cost-effective, low Fish Meal aquaculture feeds. Modern standardization of the rendering process has resulted in new generation products with higher digestibility and less variability than in the past. Research has shown they can successfully replace, at least partially, the more expensive Fish Meal. As a result, we can expect the feed represented by this feed tag to contain a significant amount of this animal byproduct. Typical diets for salmon can contain up to 40-55% Fish Meal. It would not be unusual, however, to have Poultry By-Product Meal substitute up to half of it. Feather Meal is another byproduct of the poultry industry that is declared as an ingredient in this fish

Table 1 Likely concentrations of protein, fat, fiber, and ash of the ingredients declared in the example feed label Crude protein*

Crude fat**

Crude fiber**


Fish Meal





Poultry By-Product Meal





Blood Meal





Feather Meal




Wheat, whole



Source: International Feed; *minimum value; **maximum value


As strange as it may sound,

the best amino acid profile in a single protein fed to a given animal species is the protein present in the tissues of that same species or even related ones. Âť 49


One of the main concerns

with fish or poultry oil added as ingredients in fish diets is precisely their strength, or their high concentration of polyunsaturated fatty acids.

tag and which has received significant attention lately. Feather Meal is very rich in sulfur-containing amino acids and can thus be used as a “complementary protein” for this purpose, particularly in diets where plant proteins are also used. Blood Meal is another “complementary protein” which helps add lysine to the diet. Feather Meal has been used at much higher concentrations than Blood Meal, which should not usually exceed 2-3% of the total ingredients.

Crude fat While protein quality and individual amino acids are very important for adequate salmonid performance, crude fat and the presence of essential fatty acids are critical not only for fish performance but also fish health. Crude fat in the diet adds to its flavor, provides needed energy,

50 »

and provides essential nutrients such as long chain omega-3 polyunsaturated fatty acids (eicosapentaenoic acid, docosahexaenoic acid), and vitamins (A, D, K, etc.). In salmonid diets as well as other fish diets we need to differentiate between total crude fat (as reported in the tag) and oil in the diet. If crude fat is a good indicator of the energy added to a diet, the presence of oil (degree of unsaturation of that fat) is a good indicator of the presence of essential fatty acids in that diet. There are concerns that high replacement of Fish Meal protein with Poultry ByProduct Meal protein can adversely affect fish flesh quality, due to lowered fatty acid content (particularly eicosapentaenoic and its ratio with docosahexaenoic acid). Let’s suppose the formulation of this diet included 25% Fish Meal and 25% Poultry By-Product Meal (50:50). Both have approximately 10% crude fat with the rest of the ingredients supplying very little. The total fat added with these two ingredients would be 5% (50%*0.10) however the ration calls for not less than 19% thus there will be a need for 14 percentage units more of crude fat that need to be added to the final feed. However, not any fat! From the ingredients, we know that it would be unsaturated fat (Fish Oil and/or Poultry Oil) rich in polyunsaturated fatty acids. One of the main concerns with fish or poultry oil added as ingredients in fish diets is precisely their strength, or their high concentration of polyunsaturated fatty acids. The presence of these double bonds (unsaturation) in their molecules makes them very susceptible to rancidity. There are two types of rancidity: oxidative and hydrolytic. Although both can be of concern, with oils added to fish feed oxidative rancidity is the most frequent. Also known as auto-oxidation, it happens when unsaturated fats in the presence of oxygen and ultraviolet

radiation break down in primary oxidation products (peroxides) and subsequently secondary non-palatable and toxic oxidation products such as aldehydes and ketones. Key environmental conditions that promote rancidity are: temperature, time, light, water, and some metal catalysts. One additional problem is that natural antioxidants present in feeds are vitamins such as A and E. Therefore, oil rancidity can lead to induced deficiency of these vitamins even when added to the feed. Key management strategies are to store fish feed in cool places away from direct light exposure, and use it within a reasonable period of time after the manufacture date. In addition, synthetic antioxidants such as Ethoxyquin are routinely added to feeds, as can be observed in this feed tag. Related to this is another very important piece of information from this feed tag, the date of manufacture. Needless to say we want freshly manufactured food. The longer the food stays in a warehouse after processing, the greater the chances rancidity can begin to occur. Even then, if possible one may want to schedule a visit to the manufacturer’s plant to verify their protocols and how long ingredients stay in the warehouse before processing. It does not matter that the feed has been very recently processed if the ingredients have been stored for a long time or under questionable conditions. It is enough to always keep in mind the conditions that can lead to the rancidity of an ingredient or finished ration: time, temperature, light and water!

Crude fiber Crude fiber in a ration consists of structural carbohydrates arising mostly from plant sources; this feed tag reports 3% crude fiber as a maximum. Depending on the species, some fish can utilize fiber to variable extents. There are appar-

ently endogenous (from the fish metabolism) chitinases and cellulases in some fish. Feed and intestinal microbes may be the source of polysaccharidases in fish feeding on nutrients containing non-starch polysaccharides. Salmons can use starch to a limited extent (approximately 9-10% of the diet) but being a carnivorous species their nonstarch polysaccharidase activity is likely negligible and thus fiber in the diet should not exceed 3-4%. Whole Wheat contains roughly 3% and some of the other ingredients also report similar values as maxima. A cereal grain such as Whole Wheat is oftentimes used to improve the extrusion process because of starch content. In addition, and since more ingredients have way more than the 45% protein required, wheat is used to bring the total protein down, closer to 45%.

Minerals, vitamins and other additives Minerals and vitamins are usually purchased by the feed manufacturers and added as premixes at the moment of mixing the ingredients. Very large feed manufacturers oftentimes make their own premixes. This practice, however, requires maintaining additional inventories and the need for special equipment, making the purchase of premix a

Crude fat and the presence of essential fatty acids are critical not only for fish performance but also fish health.

more convenient method of adding these ingredients. Whatever the choice it is very important for the vitamins (particularly A. D, and E) to be protected from rancidity as suggested above for other ingredients. Macro-minerals (e.g. calcium and phosphorus) are also provided through the ingredients. The advantage is that the chemical forms that are found in animal products have greater bioavailability for the fish than those present in plant concentrates. Phosphorus in plant-derived ingredients in particular is in the form of phytate, which is not utilized by the fishes’ enzymes. This poses a two-fold concern. First, the fish will not receive adequate phosphorus for its metabolism, and secondly there will be more phosphorus excretion in the water, which leads to more contamination and eutrophication (excessive algae growth).

Final comments Feed tags can provide good information, provided we have an idea of the requirements of the particular species. They are an express guarantee for the fish farmer as to the ingredients used in the formulation of the feed. Granted, there are some aspects out of the control of the end user, particularly as related to the formulation using ingredients that take into consideration fish performance and not just price. Aspects that are within the fish farmer’s control are the use of the feed for the intended species/purpose, and storing it in a way that will protect it from rancidity. This includes not storing fish feed for an unusually long time and always keeping in mind the time, temperature, light and water rule. The length of time a fish feed can be stored without problems depends on its fat content. This salmon diet is an extreme example of a ration that should be in storage for as little time as makes sense from

The chemical forms that are found in animal products

have greater bioavailability for the fish than those present in plant concentrates.

a practical standpoint. The main reason being that it contains a very high concentration of polyunsaturated fats that can become rancid sooner compared to other, lowerfat, rations. “Expiration dates” for rations are not set in stone, as they depend on the initial freshness of the ingredients and the conditions during storage. The first signs that something is not quite right are feed refusal (decreased palatability caused by rancidity end-products), lower performance, and/or unexplainable higher death rates.

Alvaro Garcia, DVM, Ph.D. is a Professor and the Agriculture & Natural Resources Program Director at South Dakota State University.

» 51


Changing Tastes, Changing Minds By Neil Anthony Sims*

This column frequently expounds – even exalts, perhaps - on the mounting accumulation of scientific evidence that supports the responsible expansion of offshore aquaculture.

Courtesy of NOAA.


hilst a decade or so ago there was a dearth of peer-reviewed literature on the subject, there is now a profusion of evidence that is not only endorsing, but is exhortative and assertive. Not only can we expand aquaculture offshore, but we should … we must! A growing body of government researchers and independent academics are publishing, and are beginning to also proselytize. We can add to this library, now, two more seminal studies. Aaron Welch and colleagues from University of Miami’s Rosenstiel School of Marine and Atmospheric Studies have now published a compre52 »

hensive analysis of water quality and benthic impacts around the world’s largest offshore fish farm – the Open Blue cobia operation in Panama. And the Consortium on Ocean Leadership – an association of the most respected marine research centers in America – has recently published a collective assessment of the current constraints, potential risks and possible benefits that could flow from an offshore aquaculture industry in the U.S. And then also let’s consider - with some breathlessness - the even more astonishing revelations of the general public’s current thinking around offshore aquaculture. It’s not what we fear that they think; it’s not what

the most vocal naysayers may vent about. Arlin Wasserman’s “Changing Tastes” study asked folks what they actually want to eat, and why. It finds that consumers across the US are much more inclined to accept farmed seafood than anyone suspected, and they show a particular preference for farmed seafood that is denominated as of “offshore” origin. Offshore aquaculture, it seems, plays well in Peoria. Aaron and his team’s publication on the Panama monitoring (https://onlinelibrary.wiley.com/ doi/full/10.1111/jwas.12593) was the culmination of five years’ worth of field-work, with Niskin bottles, probes and grab samplers, bouncing around the briny in small boats some 13 km off the Costa Arriba region of Panama (on the Caribbean side of the isthmus), in 55 – 65 m deep water. Over the course of the study, the Open Blue operation has scaled from 16 Sea-Station net pens, each around 6,400 m3 in volume, to a final count of 22 net pens, holding an estimated 1,360 T of cobia. The upshot of the analyses showed – almost entirely – no significant differences in water quality between the sites up-current, and the sites down-current of the net pen array. Some of the parameters (particulate carbon, at some specific depths) actually showed higher levels at the up-current sample sites. (So … the pens were cleaning up the water!? Filter-feeders on the net pen mesh? Go figure …). There was, however, a statistically significant decrease in dissolved oxygen (DO) throughout the water column, as the water moved past the net pens. These differences were of the order of 1 - 3 hundredths of a ppm. As ambient DO levels were of the order of 6.5 ppm, this represents less than a 0.5% reduction in oxygen. So OK, there was indeed a “statistical significance,” but in the open ocean, this is far, far from any ecological significance; i.e. nowhere near any detrimental impact that could be any real cause for concern.

Courtesy of Open Blue Cobia.

The benthic sampling revealed “a trend toward increased organic loading in the benthos” underneath the net pens, but one would suspect that the same increase in organic loading could be found in the pasture behind the back end of a cow. In any case, temporal variation in substrate indicators (both seasonal and year-to-year) proved to be greater than the effects of distance from the net pen array. The authors do betray some of the bias that we all might share, when they concluded that these results provide “a reason for cautious optimism.” But they can be forgiven – this bias is borne of experience, and frustration. So overall, this paper reaffirms the broad generalization that we have come to understand, and advocate for – in deeper water, further offshore, fish net pen systems (at proper densities, and with proper management) can function within the assimilative capacities of the ecosystem. The ni-

In deeper water, further offshore, fish net pen systems (at proper densities, and with proper management) can function within the assimilative capacities of the ecosystem.

trogen or phosphorus inputs to the ocean that might possibly be considered a “pollutant,” can become a “nutrient” in offshore waters, stimulating primary productivity (which is, in the main, a good thing). The authors recognize this, also noting that “nutrients of the sort discharged by aquaculture facilities are not, ipso facto, pollution,” and there are often benefits, in terms of increased productivity of fisheries around aquaculture sites. In our modern oceans, where over 90% of the big fish are already gone, and almost all the planet’s fish stocks are exploited at or beyond their sustainable catch levels, increased productivity might be something that would be celebrated; or at least given a listen. Take heart: some are listening. A forum in Washington, D.C., on October 26th, last year, posited the pointed question of “U.S. Offshore Aquaculture; Will we fish or cut bait.” This event was convened by the Consortium for Ocean Leadership (CoL), in conjunction with the Meridien Institute (with the apt tag-line: “Connecting people to solve problems”), and a slew of sponsors (from NOAA, to industry and certification entities, advocacy groups and foundations). CoL is not well known outside of academic and policy circles, for the simple reason that they are an agglomeration of academics who convene these annual forums to consider policy questions (… “academics” … “policy” … your eyes are starting to roll back, right? Don’t doze off on us, yet, please …

stay with me!). See … CoL are the folks that run and staff the nation’s marine laboratories. They are dedicated, professional marine biologists and oceanographers; researchers with no vested interest in anything other than healthy oceans, and sound science. If U.S. offshore aquaculture ever wished for an objective hearing from a jury of learned peers, then this was going to be the day. The goals of the one-day event were to “develop a clear, shared understanding of the current state of offshore finfish aquaculture … opportunities and challenges” along with “consideration of the science, environmental safeguards, investment opportunities … (and) … specific areas of action … to advance informed decision making in this emerging industry.” If this sounds familiar, then it does bear a disquieting similarity to any number of august gatherings and groupings over the last couple of decades, which have all amounted to … um, well … not much progress at all, really, to be brutally honest. There was the usual array of PowerPoints, podium thumping and panelist discussions that came to the usual conclusions (well – the conclusion with which most of us are all-too-aware), that (dang it!), we should be growing more of our own fish in U.S. Federal waters. It makes economic sense. It makes environmental sense. It could create employment. It could improve American consumers’ nutrition. The main impediment to this consummation most-devoutly-to-be-wished is that the “regulatory processes in the U.S. are complex, unpredictable, and lengthy,” and are discouraging of investment. Ok, we get it, already. We got it. We all knew this, right? However, what was perhaps helpful to us all from this event was that – this being a policy gabfest in Washington, DC. - a number of Congressional staffers were in the audience. Many of them probably already knew these imperatives and impediments too, but it seemed that they were grateful to hear the overwhelming consensus of such » 53


an authoritative, unbiased body. The conclusions from the Forum could therefore prove helpful in moving forward legislation that might actually stand a snow-ball’s chance in Chad. The forum concluded with almost unanimous, rousing endorsement of the AQUAA Act (formerly known as the Wicker Bill – the “Advancing the Quality and Understanding of American Aquaculture” Act). This is the revival of legislation to provide a sound regulatory framework for aquaculture in U.S. Federal waters, which is being pursued most capably and vigorously by the SATS coalition (Stronger America Through Seafood – you are not yet a member? Write to me, and I will connect you!). The CoL Proceedings - recently published online for the whole world to see (https://oceanleadership.org/ wpcontent/uploads/2019/01/2018_ IndustryForum_ProceedingsDocFinal.pdf) – concluded that the AQUAA draft provided a “viable starting point (which), with modifications … focus54 »

ing on environmental safeguards … would not only ensure sustainability and viability but also attract the necessary bipartisan support.” (Implying perhaps, that bipartisan support is more highly desirable, but more difficult to achieve, than sustainability or viability. In Washington, D.C., today, that may actually hold true!). The legislation will go nowhere if Congress is still swayed by the Orwellian chorus of “Farmed cows good, farmed fish bad!”. But it is clear - the truth is no longer black and white, but is rather a spectrum of blue and green hues, with some gray in between. It will be a sad day for American consumers – and American oceans – if Congress is content to metaphorically and literally sit on the beach, gaze out at empty, barren seas, and not change a thing. But Congress is meant to reflect the will of the people… and people, change is indeed a-coming! Nowhere is this more comprehensively and compellingly underscored than by Arlin Wasserman and his colleagues

at Changing Tastes and Datassentials in their recent consumer study entitled “Aquaculture – Mariculture: U.S. Market Insights and Opportunities” available through their website (www. changingtastes.net). A pdf of the study summary is available by googling “changing tastes mariculture insights”. This study found that fully one quarter of U.S. consumers intend to eat less meat, with beef consumption projected to decrease by 20% over the next decade. So … what then will they eat? Consumers’ top choice to replace beef was – (wait for it … TahDah!) - fish and shellfish! Even more - “offshore” was found to now be a strongly favored differentiator in seafood selection. Over a third of U.S. consumers believe that offshore aquaculture already provides “a substantial share” of the fish they eat. (Oh, if that were but true!). The study interprets this misperception as an opportunity, demonstrating that there is already “pre-acceptance” of offshore fish farming, and heralding “market recognition and support” for offshore operations and products. And, most tellingly, “a quarter of consumers and operators believe (offshore fish farming) is better for the environment than wild capture fishing.” Well! Who knew?! Savor that conclusion for a moment, dear reader, then rise up, and recommit yourself to the future of fish … beyond the blue horizon. The tide is turning in our favor. I can almost taste it!

Neil Anthony Sims is co-Founder and CEO of Kampachi Farms, LLC, based in Kona, Hawaii, and in La Paz, Mexico. He’s also the founding President of the Ocean Stewards Institute, and sits on the Steering Committee for the Seriola-Cobia Aquaculture Dialogue and the Technical Advisory Group for the WWF-sponsored Aquaculture Stewardship Council.

» 55


Making Sense of USDA Siluriformes Inspection By: Evelyn Watts & Katheryn Parraga

Fish within the Siluriformes order are a diverse group, primarily found in fresh water. There are 3,093 species reported in this order, including 36 families and 478 genera.


atfish are the most abundant group within the Siluriformes order. In the U.S., both farm-raised and wild-caught siluriform catfish are processed. Channel catfish (Ictalurus punctatus) are primarily domestic farmraised. Although the industry is based on large-scale farming operations in the southeastern region, smaller farms can be found in many states. On the other hand, the wild-caught industry’s most commonly harvested species are Blue catfish (Ictalurus furca56 »

tus), Flathead catfish (Pylodictis olivaris) and Yellow catfish (Ameriurus natalis). Some other species such as Gafftopsail catfish (Bagre marinus), and Bullheads [Brown bullhead (Ameriurus nebulosus) and Black bullhead (Ictalurus melas)] are harvested in low amounts. In 2016, these wild-harvested species were reported to have a combined total production of 13,143,000 pounds. Other fish in the Siluriformes order, usually exported from Asia, are Swai and Basa, members of the Pangasiidae family. In addition, the Armored

Catfish from the family Loricariidae has become an invasive species in the state of Florida (Table 1). In the U.S., apart from farming operations, catfish are found in natural waters such as large reservoirs, lakes, ponds and streams characterized by sluggish, moderate and occasionally fast flows. Most growth occurs during warm water temperatures (85˚F). The spawning season can go from February to August depending on the location. Usually in the state of Mississippi, the spawning time is in May. The main production of farmraised catfish in the U.S. occurs in the southeastern states of Mississippi, Arkansas, and Alabama, where Channel catfish are usually raised in earthen ponds. The proliferation of the catfish industry developed in the mid to late 1900s in the Delta region. The principal areas of catfish production are the alluvial valley along the Mississippi River that is in western Mississippi, northeastern Louisiana, and southeastern Arkansas (also known as the Delta Region). This area has 73,618 acres of catfish production. In 2016, the gross farm value of catfish production in U.S. was $363 million, the U.S. Wild-caught catfish value was $6.7 million, and the total value of catfish imports was $414 million. From 2000 to 2016, domestic farmraised catfish showed a decrease, while catfish imports continued to increase (Figure 1). In 2017, catfish imports declined, but in 2018 the value recovered and surpassed the value of previous years (Figure 1). The National Oceanic and Atmospheric Administration (NOAA) had not yet released information for domestic aquaculture values for 2017 and 2018 at the time this summary was compiled (Figure 1). From 2000 through 2017, wild-caught catfish volumes and values showed a declining trend (Figure 2). In the U.S., Louisiana is the largest harvester of wild catfish, followed by Maryland and Virginia, where the blue catfish in particular is considered an invasive

Figure 1 Domestic catfish production for farm-raised compared with total catfish imports from 2000 through 2018. Farm-raised

Total imports thousand of dollars

The main production of farm-raised catfish


in the U.S. occurs in the

Thousand of dollars


southeastern states of Mississippi, Arkansas, and


Alabama, where Channel $300,000

catfish are usually raised in earthen ponds.























of the safety of all seafood and seafood characterized products; however, in 2008 in the Food, Conservation, and Energy Act (Farm Bill) congress moved the inspection of fish in the order Siluriformes to the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA/FSIS). This effort began in 2001, because catfish producers were complaining about imports of cat-

species (Figure 3). Large farm-raised processors can process as much as 400,000 pounds per week, while small farm-raised and wild-caught processors can account for as little as 200 to 9,000 pounds weekly.

Mandatory Inspection of Fish of the Order Siluriformes Historically, the U.S. Food and Drug Administration (FDA) was in charge Figure 2

Wild-caught catfish pounds per year and dollars per pound from 2000 through 2017 Thousand of pounds Lineal (Thousand of pounds)

Dollars per pound Lineal (Dollars per pound)




$0.60 $0.50

12,000 $0.40

10,000 8,000




4,000 $0.10





















Dollars per pund

Thousand of punds


fish affecting local prices. The Catfish Farmers of America (CFA) trade group insisted that there was unfair trade regarding the importation of catfish. In the 2002 Farm Bill, congress amended the Federal Food, Drug, and Cosmetic Act (FD&C Act), stating that only fish classified in the family Ictaluridae can be labeled as ‘catfish’ and recommended importers to use alternative names for nonictalurid species. However, this was not the first time catfish labeling had been addressed. Some state agencies such as the Louisiana Department of Wildlife and Fisheries (LDWF) had regulated ‘catfish’ labeling since 1991 (LA Statutes Title 56) (Table 1). In 2008, the Farm Bill gave the USDA/ FSIS the authority to determine which fish the term ‘catfish’ would apply to, and amended the Federal Meat Inspection Act (FMIA) adding catfish as an amenable species. The amendments were not to apply until the date on which the Agency issued final regulation. In February 2011, the USDA published the proposed rule “Mandatory Inspection of Catfish and Catfish Products,” where the agency proposed to inspect catfish under the same regulations governing the inspection of other species under the FMIA, with some modifications. In addition, USDA recognized that there are situations in which wild-caught catfish are also processed for com» 57

POST-HARVEST Figure 3 U.S. Wild-caught Catfish pounds harvested in 2017 by states, data obtained from the National Oceanic and Atmospheric Administration - National Marine Fisheries Service. 6,000,000

On December 2, 2015,


USDA published the final rule


“Mandatory Inspection of fish of the order Siluriformes and

Punds / year


products derived from such



mercial distribution. Furthermore, the agency settled on two options for defining ‘catfish.’ The first option recognized ‘catfish’ to be only fish of the family Ictaluridae and the second option was an order definition including all fish under the order Siluriformes. On December 2, 2015, USDA published the final rule “Mandatory Inspection of fish of the order Siluriformes and products derived from such fish.” The final rule became effective on March 1, 2016. In this rule, domestic as well as foreign facilities that process Siluriformes fish and fish products for wholesale are required to comply with the USDA/ FSIS inspection program. However,

Figure 4. USDA stamp of inspection.

58 »









North Carolina






USDA/FSIS provides an exemption for retail stores and restaurants. Under this rule, Siluriformes processing facilities had to comply with facility standards, develop and implement protocols and recordkeeping associated with Sanitation Performance Standards (SPS), Sanitation Standard Operational Procedures (SSOP’s) and

Hazard Analysis and Critical Control Points (HACCP) to assure the safety of the product. After implementing food safety programs, facilities have a period of 90 days to validate them. The Siluriformes rule included an 18-month transition period to allow catfish slaughterers and processors to understand and comply with the Food Safety Inspection Service (FSIS) food safety requirements. During this time, FSIS worked with farm-raised and wild-caught catfish processing establishments provid-

Table 1 List of common names recognized by USDA for Siluriform fishes. Order


Common Name




Swai, Sutchi, Striped Pangasius,


Tra, Basa Ariidae

Gafftopsail catfish, Hardhead catfish


Armored catfish, Suckermouth catfish

ing guidance to ensure compliance. To assist the industry, on March 24, 2017, FSIS published the “Compliance Guideline for establishments that slaughter or further process Siluriformes fish and fish products.” In the guideline, USDA/FSIS only addresses hazards associated with farmraised catfish processing. In many parts of the country outside of Arkansas, Mississippi and Alabama, independent farm-raised catfish producers process their harvests on a much smaller scale, relying on local markets and consumers. During the transition period, FSIS estab-

lished inspections at all hours of operation for facilities processing more than 5,000 pounds per week, quarterly inspections for facilities processing 1,000 to 4,999 pounds per week, and inspections for facilities processing less than 1,000 pounds per week at a frequency “to be determined.” At the end of the transition period, FSIS adjusted inspection coverage from all hours of operation to once per production shift for all processing facilities. Facilities are granted 40 hours a week (Monday-Friday) of inspection at no cost; however, processors are required to pay for overtime, holidays, and weekends. Full enforcement has been in place since September 1, 2017. During the transition period, FSIS conducted random and targeted sampling and testing of domestic and imported Siluriformes fish. Testing included drug, pesticide, and other chemical residues, as well as for Salmonella spp. to determine the baseline prevalence and levels on raw Siluriformes fish and fish products. In the final rule, USDA stated that both farm-raised and wild-caught fish will be inspected by FSIS. Even

In the final rule, USDA stated that both farm-raised and wild-caught fish will be inspected by FSIS

though hazards as well as harvesting procedures differ between farmraised and wild-caught, the rule and guidance materials were developed for large-scale processors, most of which process farm-raised catfish. Whether processing farm-raised, wild-caught, domestic, or imported, all operations must display the USDA stamp of inspection (Figure 4).

Dr. Evelyn Watts has a Veterinary Medicine degree and a Master’s in Food Safety from the University of San Carlos in Guatemala, and a Doctorate in Food Science from Louisiana State University. She works with seafood processors in Louisiana assisting in regulatory compliance, as well as providing guidance on handling, processing, packaging and storage technologies.

» 59


The Cost of Regulations on

U.S. Trout and Salmon Farms By: Carole R. Engle, Jonathan van Senten and Gary Fornshell

Laws and regulations are necessary for society to operate in an orderly

fashion and to manage public resources in an effective manner for the benefit of all. Yet there are growing concerns over whether aquaculture and other businesses in the U.S. have become over-regulated.

60 Âť


his column summarizes results of the recently published study that reports on the economic effects of the implementation of regulations on salmonid (trout and salmon) farms in the U.S. A survey was conducted primarily through in-person interviews on salmonid farms in the 17 top salmonid-producing states in the U.S. (Colorado, California, Idaho, Maine, Michigan, Missouri, Nebraska, New York, North Carolina, Ohio, Oregon, Pennsylvania, Utah, Virginia, Washington, West Virginia, and Wisconsin). Every attempt was made to contact and interview every salmonid producer in each of these states. The overall response rate was quite high at 63%, with the resulting dataset covering 94.5% of the national production of trout and salmon. When asked what the greatest problem was on their farms, regulations were ranked most frequently as the #1 problem (Figure 1). While respondents mentioned a variety of other problems that included predation by birds and bears, labor issues, fish health problems and others, regulations were at the top of the overall list. The specific category of regulation that was ranked as most problematic was that of the fish health testing needed for health certificates required for interstate shipping, followed closely by testing of water discharged under the NPDES permitting system of the Environmental Protection Agency. Results of the study show that regulations create two main kinds of economic effects on U.S. salmonid farms, increased costs and lost sales revenue. Costs increase as producers spend money on testing and shipping fish for fish health certificates and water samples as required for NPDES permits, manpower for recordkeeping and reporting, and a host of other types of costs. In addition to the increased costs, many producers reported various types of lost sales revenue that included: market sales lost as a result of regulations, sales

Figure 1 #1 Problem on U.S. Salmonid Farms. 35 30 25 % of respondents

revenue lost due to reduced production capacity as a result of regulations, and sales revenue lost due to extended delays in the permitting process that have thwarted attempts to expand production. Nationally, annual costs on U.S. salmonid farms were found to be $16.1 million, with an additional $52.5 million annually in lost revenues (Figure 2). Regulatory costs were found to account for 12% of total costs and lost revenues were equivalent to 28% of total costs, when averaged across farms. The regulations that resulted in the greatest cost increases on U.S. salmonid farms were those related to effluent discharge regulations, constituting 62% of the increased costs on U.S. salmonid farms. Other local and county regulations constituted 26% of the increased costs on farms, while fish health testing for certificates was 7%, water rights 4%, and food safety regulations 1% of total regulatory costs. The costs of regulations were found to result in a far greater negative effect on smaller farms than on larger farms (Figure 3). In fact, the regulatory cost per pound of fish produced on the smallest size of salmonid farm was 18 times greater than that of the regulatory cost per pound of fish produced on the largest size category of farms. Regulatory costs were also found to be nearly a third greater per pound on farms that

20 15 10 5 0

Regulations Depredation

Fish health

produced primarily for recreational markets as compared to those that sell into foodfish markets. Foodfish producer regulatory costs resulted mostly from effluent discharge regulatory actions, while for farms that sell primarily into recreational markets, the greatest proportion of the negative economic effects were those associated with fish health testing and certifications required to transport live fish products to other states. Regulatory costs were found to function mostly as fixed costs on salmonid farms. The only effective management response to increasing fixed costs is to increase the scale of production and produce greater volumes. Many respondents were un-


Water access



able to expand production, even with growing demand for locally-raised trout in their market areas, due to regulatory restrictions that prevented expansion. Thus, it appears that the regulatory environment has forced a number of salmonid producers to operate at less-efficient production scales. In an earlier study, van Senten et al. (2018) found that the regulatory environment also resulted in inefficiencies on U.S. baitfish/sportfish farms. In addition to preventing farms from making the adjustments necessary to cover the increased fixed costs of regulations, inefficiencies also resulted from owners and managers spending time on required record-keeping and reporting activi-

Figure 2 Economic Effects of Regulations on U.S. Salmonid Farms

The specific category of regulation that was ranked as most problematic was that of the fish health testing needed for health certificates required for interstate shipping.

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The only effective management response to increasing fixed costs is to increase the scale of production and produce greater volumes.

ties that reduced time available for farm-level innovations and market development. Results of this study show that the way regulations have been implemented in the U.S. may have forced a number of farms out of business in spite of strong demand for locally raised trout. Not only does data from

the Census of Aquaculture show a decline in the number of salmonid farms, national import data show that trout imports have more than doubled from 2012 to 2016. The salmonid producers who responded to the survey recognized the need for regulations that protect environmental quality and that reduce

the spread of fish diseases. There are, however, serious problems related to the on-farm cost burden that has developed as a result from the total suite of record-keeping, reporting, and testing that U.S. producers must comply with. The negative economic effects measured in this study are of a magnitude that calls for substantial efforts to develop alternative ways to implement regulations in the U.S. 1) that are less redundant, 2) that reduce the time burden related to recordkeeping, reporting and the frequency and cost of testing, and 3) that lead to an overall reduction in the substantial on-farm regulatory burden on trout and salmon farms in the U.S.

Figure 3 Cost of Regulations by Farm Size. $3.50

Mean regulatory cost ($/lb)

$3.00 $2.50 $2.00 $1.50 $1.00

Carole R. Engle & Jonathan van Senten: VA Seafood AREC, Virginia Tech University Gary Fornshell: University of Idaho

$0.50 $0.00 < 20,000 lb

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20,000 to 119,999 lb

120,000 to 500,000 lb

> 500,000 lb

Adapted from: Engle, C.R., J. van Senten, and G. Fornshell. 2019. Regulatory costs on U.S. salmonid farms. Journal of the World Aquaculture Society 50(3). DOI: 10.1111/jwas12604

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Use of antibiotics

in the major salmon producing countries According to the World Health Organization between 60-80% of all By Asbjørn Bergheim*

antibiotics worldwide are used in food production.


ntibiotics have been widely used in aquaculture to treat and prevent bacterial diseases. In many countries, excessive use of antibiotics has caused concerns due to development and prevalence of bacterial resistance, food safety hazards and environmental issues. Nevertheless, the development of resistance and dissemination of antimicrobial-resistant genes (ARG) is poorly understood. The high productivity of salmonid farming, characterized by high fish density, has resulted in an increased susceptibility to diseases caused by viruses, bacteria, fungi and parasites. Antibiotics are typically administered through feeding and the first contact with microorganisms occurs in the intestine of the fish. In the late 1980s, an antibacterial drug use peak in the Norwegian salmon industry was closely connected to numerous outbreaks of vibrioses. The highest use of active antibiotic substances reached 450 g per ton of salmon produced (in 1987). Development of an effective vaccine against cold-water vibrioses then resulted in a steep decline in antibiotic use. Today, salmon farming in Norway uses some 500 kg of antibiotics annually, equivalent to less than 0.5 g per ton of salmon produced. Aquaculture only represents 0.4% of the country’s total antibiotic use according to the veterinary authorities. The successful control of bacterial infections in Norwegian aquaculture is “an important contribution to show it is possible to be a global actor in sea-

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Columnaris disease (Flavobacterium columnaris) in the gill of a chinook salmon. Photo: U.S. Fish and Wildlife Service.

food production with negligible risk to human health in terms of promoting antibiotic resistant bacteria” (citation: Miranda et al. Front. Microbiol. 2018). Antibiotic use on Scottish salmon farms peaked in 2006 (5.5 tons total). However, the quantity gradually declined over the following years (SEPA). In 2015, only 4% out of 136 Scottish farms used antibiotics. Salmon production in Chile has one of the highest rates of antibiotic consumption per ton harvested worldwide (Figure 1). Over the last years, the disease piscirickettsiosis (P. salmonis) is considered the main threat to the Chilean industry. There is no effective vaccine to treat this disease. Florfenicol is by far the most frequently used antibacterial drug in this case, representing more than

300 tons annually used in marine farms two years ago. Florfenicol use almost doubled between 2013 and 2016. Taking into account that the geographical area used by Chile for salmon farming is only one fourth of that used by Norway the use of antibacterials is of high concern to some observers. At least 70% of the total feedsupplied antibiotics in mariculture is likely to be lost through leaching from pellets and faeces. Up to 20% of a commonly used drug, oxytetracycline (OCT), can be leached from the pellets in 15 min. Residues of OTC and oxolinic acid (OA) were found in sediments beneath salmon cages in Norway during the period with elevated use, while more recent sediment studies in Southern Chile rarely detected any antibiotic residues

Figure 1 Use of antibiotics in Chilean Salmon Industry 2005–2016. Unit: g per ton of harvested salmon (modified from Miranda et al. 2018). Use of antibiotics in Chilean Salmon Industry 2005-2016

700 600 500


400 300 200 100 0



2007 2008


At least 70% of the total feed-supplied antibiotics in mariculture is likely to be lost through leaching from pellets and faeces.



2012 2013

2014 2015 2016

at marine farms. The persistence of antibacterial residues in sediments seems to be higher at salmon farms in freshwater than in those below marine farms. Increased levels of antibiotic resistant bacteria (ARB) in the digestive systems of fishes are well documented from several studies. The evolution of resistance of P. salmonis to antibiotics has been demonstrated. ARBs are easily transferred through feces to the water column and local sediments. Lost medicated feed can

Netting Atlantic salmon. Photo: U.S. Fish and Wildlife Service, National Digital Library.

also be consumed by wild fish nearby the salmon cages thus increasing the levels of ARBs in these fishes too. A Chilean study also indicated antibiotic residues in fish muscle, and such residues can enter the human intestine if the fish is consumed uncooked (e.g. sashimi, sushi). Regulations on the use of antibiotics in aquaculture vary widely between countries. In some countries the regulations are strict and only a few antibiotics are licensed for use in aquaculture. For example, in Norway it is mandatory to report the amount of antibiotics used and retain records of prescriptions. The US Food and Drug Administration has approved just four antibiotics for specific uses in aquaculture. There are 12 different types of generic and 25 branded antimicrobials for use in salmonids in Chile. Chilean researchers formerly pointed out the urgent requirement for the application of strict controls to reduce the overuse of antibiotics and implementation of a regular surveillance program to detect the prevalence of ARGs in the environment. The current Fisheries and Aquaculture Law in Chile prohibits application of antimicrobials in a preventive way as well as any use harmful to human health. Each fish farm must demonstrate – and issue a declaration of guarantee – that the concentrations of pharmaceutical products in fish do not exceed the limits established by the Chilean authority.

Dr. Asbjørn Bergheim is a consultant at Oxyvision Ltd. in Stavanger. His fields of interest within aquaculture are primarily water quality vs. technology and management in tanks, cages and ponds, among others. asbjorn@oxyvision.com

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– The Good Flavors of Oysters By Michael A. Rice*

It has been known for eons by ostreophiles (lovers of oysters) that

oysters of the same species will taste very differently depending upon where they are grown and the season of the year.

Figure 1. A green-gilled Crassostrea gigas oyster grown in the Marennes Oléron Bay Region and finished in claires for greening of the gills with marennine algal pigment. Photo courtesy of Cagette Canteen and Deli, Bangkok, Thailand.


his variation in taste in oysters parallels very closely a similar phenomenon that occurs with varietal wine grapes. In varietal wines, terroir is the concept that their flavors are derived from a sense of place. The vineyard’s soil character66 »

istics, terrain and drainage, sunlight, water quality, microclimate, etc. all contribute to a unique flavor that encapsulates a particular place and time. Those who market wines are well-accustomed to the value of terrior, as wines from particular vineyards and chateau wineries can com-

mand very premium prices due to their reputations, which have built up over time as a result of the terrior of their grapes. In French, the word mer means sea, so the portmanteau term merroir was coined to describe a sense of terroir for oysters, and the term has become popular around oyster bars, particularly in North America.Each oyster is intimately impacted by the body of water it comes from, the algae it feeds on, the strength of currents and tides, the mineral content of the seafloor, rainfall, temperature, season and more. Although oysters can be the same species and grown in a similar manner, just a difference of a few hundred meters in location can have a big effect on their flavor. The flavors of oysters are most often described as having three phases: an initial first impression stage involving saltiness, a second stage involving body and sweetness, and a final third stage, often described in terms like floral, fruity, or metallic aftertastes or finishes. But what are the factors that affect the flavors of oysters and how? Of course the species of an oyster has a great influence upon its taste. For instance, various popular oysters such as the Eastern oyster, Crassostrea virginica, the Pacific oyster Magallana (Crassostrea) gigas, the Olympia oyster, Ostrea lurida and the European flat oyster, Ostrea edulis, all have distinctive flavors that are characteristic to the species. Pacific oysters have what is described as a robust full bodied flavor, whereas Eastern oysters are often described as having a salty taste of the sea and a more delicate, sweeter flavor. The Olympia and European oysters are frequently described as having a fullbodied flavor but with a slight metallic finish. The merrior of an oyster is most prominently experienced when eating oysters of the same species, but harvested at different times of the year or harvested from different water bodies. One of the largest differ-

In French, the word mer means sea, so the portmanteau term merroir was coined to describe a sense of terroir for oysters, and the term has become popular around oyster bars, particularly in North America.

Figure 2. Oyster claires near the village of La Cayenne, in the Marennes-OlĂŠron region of France.

ences in taste of oysters at different times of year has to do with how ripe the gonads of the oysters might be during a particular season. During the spring season in the northern hemisphere for example, oysters emerge from inactivity during the cold winter and are met by lengthen-

ing days and warming waters. These conditions are favorable for spring phytoplankton blooms and intense filter feeding by the oysters. During this period of abundant food and relatively cool waters, oysters undergo rapid gonad maturation and build-up of an energy storage mol-

ecule called glycogen that is a complex carbohydrate consisting of a string of glucose (sugar) molecules in a chain. Oysters are the fattest just prior to their late spring or early summer spawning period, with ripe gonads, displaying a creamy-colored appear-

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Figure 3. Matunuck Oyster Farm, South Kingstown, Rhode Island USA. Photo by M.A. Rice.

ance to the soft tissues that fill up the shell cavity of the oyster. This is the time when oysters have their sweetest flavor and pleasing texture. Later in the summer, when the oysters have spawned out, their meat is thinner and glycogen is expended, so their taste becomes more bland.

The flavors of oysters are most often described as having three phases: an initial first impression stage involving saltiness, a second stage involving body and sweetness, and a final third stage, often described in terms like floral, fruity, or metallic aftertastes or finishes.

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Oysters in the temperate zone will typically regain some stored glycogen, and thus some their flavor, as the result of autumn phytoplankton blooms and building up glycogen stores to fuel their next overwinter period of low temperature inactivity. The salinity of growing waters also has a profound influence on the flavors of oysters. Oysters, like many marine invertebrates, physiologically adapt to higher or lower water salinities by adjusting the concentration of dissolved substances in their cells to match the salinity or osmotic concentration of their aquatic environment. This physiological process of maintaining relatively constant cell volume by oysters in variable salinity is referred to by physiologists as osmoconforming, or matching the osmotic pressure of fluids inside and outside of the cells. If the concentration of dissolved (osmoti-

cally active) molecules inside the cell is higher than the concentration of dissolved osmotically active ions in the seawater, then water will be drawn into the oyster cells from the seawater and the cells will swell, or even burst if the concentration difference is drastic. Conversely, if the concentration of dissolved osmotically active ions in seawater becomes higher than the osmotic concentration in the oyster cells, the cells will shrink in volume as water is drawn out of them. Seawater, of course, is primarily made up of sodium and chloride ions, and to a lesser extent magnesium, sulfate, calcium and other ions and molecules as well that generally impart a salty taste. However, the primary osmotic solutes inside oyster cells, and the cells of many other delicious marine invertebrates, are free amino acids. These are un-

One of the largest differences in taste of oysters at different times of year has to do with how ripe the gonads of the oysters might be during a particular season.

combined amino acids that could, if assembled, become protein chains. For example, the free amino acids that are most abundant in high concentrations in Pacific oyster tissues are glycine, alanine, serine, aspartic acid, and glutamic acid, along with the non-protein amino acid, taurine [See: Rice and Stephens. 1987. Aquaculture 66:19-31]. These free amino acids impart a rich pleasant flavor to oysters, and other invertebrates, that the Japanese call the umami taste. Indeed, one free amino acid, glutamic acid, in its monosodium form (MSG) has been used for many decades as a food flavor enhancer. And umami taste receptors have been discovered on the human tongue, providing a neurophysiological basis for adding umami to the list of basic human tastes that have traditionally included sweet, sour, salty and bitter [See: Chaudhari, Landin, and Roper. 2000. Nature Neuroscience 3(2): 113-119]. The overall concentration of free amino acids in oyster tissues has a profound influence on oyster taste. When oysters and other osmoconforming invertebrates adapt to low salinity water they lose free amino acids in their cells, and as a result, they assume a bland ‘washed out’ flavor. Conversely, when the same oysters are raised in higher salinity waters, there is a gain in free amino acids in their tissues and a rich umami taste

comes through. It is for this reason that oysters grown in higher salinity waters are often sought after as having good merrior. Salinity is not the sole criteria for good merrior. Different trace minerals, in combination with salinity, temperature, and time of year will determine the timing of various phytoplankton blooms that feed oysters. However, phytoplankton blooms occur in various patterns: as cycles, trends, fluctuations, unusual events and irregular pulses. And these can occur at various time scales: hourly or less, daily, seasonally, annually or over decades, and even chaotically, at varying frequencies (See: Smayda. 1998. ICES Journal of Marine Science 55: 562-573). Since different phytoplankton have differing nutritional value to oysters and can also impart different flavors, it is no wonder that locations prone to having blooms of favorable phytoplankton strains with greater frequency are the best for good merrior. There are known species of phytoplankton such as the chain-forming diatom Skeletomema costatum and boat-shaped diatoms of the genus Navicula, among others, that are known to impart good flavor to oysters, so oyster grounds in areas with frequent blooms of favored phytoplankton species would have the best merrior. The oyster farmers likely to have the best understanding of the marketing value of merrior are those of the Marennes Oléron Bay Region (45.78N, 1.11E) in the CharenteMaritime Department of Southwestern France. This region has a long history of oyster farming dating back to well before the 17th century, and part of the traditional finishing process was to place market sized oysters into salt marshes for a month or more prior to sale so that the oysters fattened and developed a greenish color to their gills (Figure 1). King Louis XIV of France was reported to be fond of these greengilled oysters, thus contributing to

their enormous popularity, at least among the French aristocracy of the time. As time went on, the practice of finishing oysters prior to sale evolved into a process of placing them into shallow managed ponds called claires in which the pond water could be managed to at least partially control the blooms of various phytoplankton species (Figure 2). It was eventually found that the greening of the oyster gills was caused by oysters eating a specific opportunistic diatom, Haslea ostrearia, that produces a water-soluble green pigment now known as marennine [See: Gastineau et al. 2014. Marine Drugs 12(6):31613189]. Management of the phytoplankton blooms in the claires has focused upon promotion of Skeletonema costatum and other diatoms for fattening and H. ostrearia for the “greening” of the oysters prior to sale [See: Soletchnik et al. 2000. Aquaculture 199:73-91]. Thus the oyster farmers of Marennes Oléron Bay truly show that assuring good merrior in oyster farming need not necessarily be a haphazard process of farm site selection, but it can also be a managed process that adds considerable value to the product.

Michael A. Rice, PhD, is a Professor of Fisheries, Animal and Veterinary Science at the University of Rhode Island. He has published extensively in the areas of physiological ecology of mollusks, shellfishery management, molluscan aquaculture, and aquaculture in international development. He has served as Chairperson of his department at the University of Rhode Island, and as an elected member of the Rhode Island House of Representatives. rice@uri.edu

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Recent news from around the globe by Aquafeed.com By Suzi Dominy*

The first tuna hatchery in North America, and the third Bluefin hatchery

in the world, is to be built in the San Diego Bay area, and the fish will be fed soy-based feeds. First Bluefin tuna hatchery to be built in the U.S. will use soybased feeds Alejandro Buentello, president of Ichthus Unlimited, LLC., will lead the hatchery project to cultivate Pacific bluefin tuna eggs, raise them to juvenile fish and distribute them to tuna farms to be raised to market maturity. This aquaculture system will be funded by a new grant from the Foundation for Food and Agriculture Research (FFAR) and augments

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ongoing support from the Illinois Soybean Association (ISA) checkoff program. “High global demand increases tuna value and induces overfishing of wild stocks,” Buentello said. “The tuna ranching industry is constrained by a stringent quota system that limits the amount of wild tuna they can catch to stock in oceanic cages. With ISA support, we successfully developed soy-based feed that can be commercially manufactured.”

The hatchery will allow tuna to be raised with sustainable feed from very early growth stages. According to Mark Albertson, director of strategic market development for ISA, the program has been funding sustainable feed research with this goal in view. For the past three years, Buentello has led ISA-funded research to develop sustainable soy-based diets for tuna. The nutritionally dense soybased diet improves feed conversion rates, reduces waste and improves meat quality. And it is made from sustainable, renewable ingredients. The ISA-funded research tested various soy-based diets for larval Atlantic Bluefin tuna in Spain, where survival rates improved at least 30 percent compared to other diets. Juvenile yellowfin tuna in Panama landbased facilities also tested formulated feed options. Building on these experiences, trials with mature, ranched Pacific Bluefin tuna in ocean net pens in Mexico confirmed the viability of the soy-based diet. The formulated diet decreases the feed conversion ratio from 28:1 with wild-caught sardines to 4:1, and reduces the amount of fishmeal and fish oil in feed by tenfold. “Soy protein is a complete protein that replaces fishmeal in diets for many aquatic species and has become the top ingredient in aquaculture feed,” says Albertson. “ISA filled a research gap in alternative protein research for tuna that existed because of the species’ complexity. We’ve laid the foundation to use soy-based feed from early development through maturity.” The ISA checkoff program research project brought together many partners to improve tuna aquaculture sustainability. Texas A&M and Kansas State universities supported research elements and evaluations and a San Diego-based factory produced feed for market-scale trials. Several competing feed companies contributed raw materials, key ingredients, blending facilities and other resources.

Chair of the F3 Challenge and F3 Judge, Professor Kevin Fitzsimmons, University of Arizona and Dr. Lin Cao, Shanghai Jiao Tong University and Stanford University at the F3 “Companies Got Talent” meeting in San Francisco.

The new hatchery will continue this trend of industry collaboration, as Ichthus Unlimited works with other tuna hatcheries, FFAR, ISA, Texas A&M University, the Spanish Institute of Oceanography and feed manufacturers. “We have developed manageable solutions for tuna production based on strong science,” says Buentello. “We are proud to work with forwardthinking leaders to develop truly sustainable hatch-to-harvest tuna farming.”

Innovative ingredients won’t be in many of your feeds any time soon While soybeans are probably the original fishmeal alternative, novel replacements seem to be grabbing the headlines in all the aquaculture media at an ever-quickening pace. I’ve talked about them a lot in this column. But how soon can we see these insect, algae and single cell proteins becoming widely available? A good ba-

rometer of the status of products in this space was the F3 (Future of Fish Feed) “Feed Companies Got Talent 2019” by-invitation meeting held in San Francisco in February. The F3 team is a collaboration of scientists, environmentalists and industry leaders sponsored by, among others The University of Arizona, University of Massachusetts Boston, Synbiobeta, Anthropocene Institute, Tides, The Nature Conservancy. (As can be deduced from this line-up, sustainability is the common denominator). The meeting brought together stakeholders in the alternative aquafeed value chain, from ingredient suppliers and feed companies, to scientists, analysts and investors. The objective of F3 is to help bring these replacement proteins and oils to market. But right now, for most of these, the market is somewhere in the future: several participants at the meeting told Aquafeed. com that they had poured millions of dollars into research, proof of concept and pilot scale production but getting to commercial scale would take not just millions more in development, but forward-thinking customers. Their customers, of course, require what feed companies demand from all their ingredient suppliers: volume, consistent availability and quality. Of the four companies who signed up for F3 Fish Oil Challenge, the follow up to the 2017 F3 FishFree Feed Challenge, Veramaris is emerging as the front-runner. They have a clear advantage: not only does their algal oil have the fatty acid profile the industry is looking for, but as a DSM and Evonik joint venture, they have the financial resources to reach commercial scale and have an outlet in their partnership with feed giant Skretting.

iFishIENCi, a new European fish feeding project Sustainable feed is also the focus of a new four-year EU Horizon 2020 project: iFishIENCi, is bringing to-

gether multiple partners in a multidisciplinary effort towards making improvements to fish farming worldwide. The project’s full title is “Intelligent fish feeding through integration of enabling technologies and circular principles.” Aller Aqua Research, AquaBioTech Group, Norwegian Research Centre and Helenic Centre for Marine Research are some of the iFishIENCi’s partners. According to Catherine Boccadoro, iFishIENCi Vaorization and Circularity Champion (Norwegian Research Centre AS) the project will target circular principles and zero waste by qualifying new and sustainable value chains for feeds, valorization of by-products and development of smart feeding technology. “It will provide important new assets for the consortium’s SMEs, fish farmers, feed producers and technology providers in the aquaculture sector,” she said.

Suzi Dominy is the founding editor and publisher of aquafeed.com. She brings 25 years of experience in professional feed industry journalism and publishing. Before starting this company, she was co-publisher of the agri-food division of a major UK-based company, and editor of their major international feed magazine for 13 years. editor@aquafeed.com

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Go Zone or No Zone? by Amy Stone*

This is an often talked about topic that has a rather polarized following.

Outside of Corona discharge with onboard oxygen unit.


n terms of system filtration components that can sterilize water, the most common methods in our industry are UV and ozone. We have already covered UV and its complexities so this time we will cover ozone. 72 Âť

be effective, the UV light must penetrate the organism and cannot be shaded by particulates in the water flow. Ozone on the other hand, can be effective even in less clear water. For most, if not all of our applications, ozone is injected into system water and when managed properly a residual level can be maintained throughout the entire system. This allows for a higher efficiency in maintaining lower overall bacterial loading. It can also remove color and odor from the water. There are also several studies on how ozone removes off flavor during purge cycles. Unlike oxygen, ozone cannot be stored because it rapidly converts back to oxygen; therefore, O3 must be generated on site. The ozone molecule does not differentiate, in that it will attack anything that is organic. It is something that requires forethought when adding it to a filtration system, as well as safety programs. However, that should not deter its use in systems with heavy loading or critical situations that require sterile water. Ozone is created when an oxygen molecule is broken into two single atoms and one atom attaches to an existing oxygen molecule. This happens in nature with ultraviolet (UV) radiation from the sun and even with lightning. When it is produced by a machine, there are several ways it can be produced. This article will review the three most common ways that ozone is produced commercially. These include using a UV light and corona discharge, using both traditional dielectrics and plasma systems.

UV Systems The UV light is possibly the simplest ozone production method of First, what is the difference be- all three ways we will discuss. These tween ozone and UV? Well, ozone systems are based on the same prinis a nonselective oxidizer that breaks ciples that are found in nature. While down anything that is organic by ozone is produced in wavelengths rupturing the cell wall. UV changes less than 240 nanometers (nm), the DNA structure of the organ- there is a specific UV wavelength ism through irradiation. For UV to for producing ozone, which is 185

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This style of machine generally has the oxygen or air source pass by a UV lamp where it creates the ozone. Machines are available in very small sizes as well as up to commercial sizes.

nanometers (nm). This is not to be confused with the effective germicidal UV wavelength range of 260270 nm for use in water. In contrast, ozone is generally destroyed when exposed to UV wavelengths between 240 and 315nm.

Corona discharge with onboard oxygen.

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Keep in mind that there are several products in the market that are purported to be able to be used for both germicidal uses in a water filtration system by passing the water through the vessel and harvesting the ozone produced in the air space between the UV lamp and the quartz sleeve. While there is a small percentage of ozone produced in those systems, it is not generally enough to be effective as an ozone source. Logically speaking, if it works to kill organisms in water, it will also have a wavelength high enough to break down the ozone molecule. This style of machine generally has the oxygen or air source pass by a UV lamp where it creates the ozone. Machines are available in very small sizes as well as up to commercial sizes. Nonetheless, the majority of this style of systems available in our industry tend to be on the smaller side. The highest concentration of ozone produced through this style of machine is about 0.2 percent by weight, which is the lowest concentration of the three styles that will be featured.

Corona Discharge Systems These systems tend to be the most prevalent and have been the ones that we have used most, until recently. Corona discharge systems operate by passing the air or oxygen through an electrical field. The electrical field is created by using a dielectric that has air space between points of electricity, which creates a “corona”. As the gas passes through, the bonds on the O2 molecule are broken and ozone is created. Corona discharge systems require that the air be very dry prior to entering the generator. Typically, an air prep system is an additional piece that needs to be included in the design. For smaller systems, on-board oxygen generators can be included which allows the generator to be turnkey. If the generator does not include an onboard dryer or oxygen generator then a separate compressor or oxygen generator should be put in-line before the ozone generator.

Plasma block dielectrics.

These systems can run on both pure oxygen or ambient air. Of course, running pure oxygen more than doubles the amount of ozone that can be produced thereby taking up a smaller footprint. Corona discharge systems can produce up to 6 percent by weight.

Plasma Systems Plasma systems are another type of corona discharge. The main difference is that they use thin layers in a block-style dielectric rather than a tubular design that is used in the more traditional generators. They are much more efficient and compact than the traditional corona discharge tube style. They also have a smaller footprint, which allows the end user to save space. This style can produce ozone at over 10 percent by weight. Major considerations “So, ozone is the best thing going,” …right? It certainly can be, but there are some things to consider before incorporating it into filtration systems.

Ozone can and is a very effective tool for cleaning water. It is heavily used in the food and beverage industry and has a place in aquaculture when applied correctly.

Plasma style generator.

First and foremost, safety! Ozone gas in air can quickly cause a very serious medical emergency. It is really strong, and will attack our lung tissue - which can, in extreme cases, cause death. Now that I have said that, I think it is also important to say that it is VERY easy to manage these safety concerns. There are well-written OSHA safety rules when using ozone in the United States and, most likely, even stronger rules in the EU. If your application is not located in the United States or European Union, it might be worth researching those rules to incorporate them into your operation. And ALWAYS follow your local safety guidelines. In terms of safety, most systems have the ability to incorporate ambi-

ent ozone monitors, which can alarm (via visual and audio means) and turn off the generator if the concentration in the room exceeds the safety set point. These monitors are critical, and require annual calibration. A consideration for using ozone is where the generator will be located. Ideally, it would be in a dedicated climate-controlled room. This is important for a few reasons. First safety, if the generator starts releasing ozone into the ambient air, a smaller space will be affected. The climate-controlled room reduces humidity and keeps the temperature stable. It is important to provide clean, cool, dry air to the machine. Ozone is destroyed with heat, so a hot room will reduce the output of the genera-

tor and rooms above about 90F will render the generator useless. If the air has high humidity, the machine will begin to create nitric acid in the dielectrics. This reduces the output of the generator and corrodes the internal working pieces. Ozone can be diffused several different ways, but most commonly, it is put into a contact tower. Its dosage is determined based on a concentration over time, so please make sure that the method chosen is able to produce the desired effects. This is something that most engineers, with experience, can size for the system. Ozone can and is a very effective tool for cleaning water. It is heavily used in the food and beverage industry and has a place in aquaculture when applied correctly.

Amy Riedel Stone is President and Owner at Aquatic Equipment and Design, Inc. She was formerly a Manager at Pentair Aquatic Eco-Systems, and she studied Agriculture at Purdue University. She can be reached at amy@aquaticed.com

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Tilapia Total tilapia imports for the month of November increased, reversing the consecutive decline seen in the previous two months. November imports were up 25.5 percent from October. Both frozen whole fish (43%) and frozen fillets (27.7%) saw increases, while fresh fillets (-8.6 %) and fresh whole fish (-40%) declined. On a year-to date basis, fresh fillets (-10.9%) and frozen fillets (-3.2%) were short compared to 2017 totals, while fresh whole fish (6.8%) and frozen whole fish (11%) were bringing in more volume compared to the same time last year. Pangasius and Channel Catfish For the second month in a row, imports of pangasius retreated, down 11.8 percent from the previous month. Compared to the same month a year earlier, import volume was up 7.8 percent. However, on a YTD ba-

sis, frozen fillet volume was down 13.4 percent. Frozen pangasius fillets from China were 340 percent higher than the previous month, which was the first month since January 2014 imports from China have been documented. Frozen channel catfish fillet imports were up 69.8 percent from the previous month and were 77.6 percent higher compared to the same month a year earlier. On a YTD basis total imports still trailed 12.7 percent compared to the same 2017 timeframe.

Frozen Channel Catfish (Ictalurus) Fillet Pricing Shipments in November entered the U.S. with a declared value of $2.12 per pound. Prices dropped by $0.46 while the import volume more than doubled from the previous month. The wholesale market continued to remain steady as prices firmed due to the implemented tariffs. The current wholesale price was listed at $3.63 per pound, $0.01 higher than the same time the previous year.

Imports of Frozen Pangasius (Swai) Fillets November imports of frozen pangasius fillets registered 18.8 million pounds, falling 11.8 percent from the previous month. However, compared to the same month a year earlier imports showed a 7.8 percent increase from November 2017. YTD figures of import volume Imports of Frozen Channel Catfish from January through November (Ictalurus) Fillets showed the 2018 total was down 13.4 Imports of frozen channel catfish percent compared to 2017, and trailing fillets registered 965,289 pounds for 30.6 percent behind 2016, the highest November. This represented a 69.8 volume year of pangasius imported percent increase from the previous into the U.S. on record with a total of month. Imports for November were 288.4 million pounds or 267.6 million slightly ahead, 4.2 percent of the pre- pounds YTD. vious three-year average of 926,419 European data also runs through pounds. November 2018 and reveals imports rose 4.8 percent from the previous month. Both U.S. (-13.5%) and European (- 9.5%) imports were down compared to 2017 YTD figures. Frozen Pangasius (Swai) Fillet Pricing According to the data from the USDOC, replacement prices for November 2018 increased $0.11 per pound from the previous month, recorded at $2.17. Please consider that the replacement cost we publish from the USDOC is not Delivery Duty Paid (DDP); therefore, if we are to properly assess this cost we must add extra to this price per pound. Thin inventory on smaller sized fillets allowed pricing to remain firm on these sizes, as well as on low moisture product.

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Imports of Fresh Tilapia Fillets In contrast, imports of fresh fillets in November totaled 3.7 million pounds, decreasing 8.6 percent from the previous month. This figure registered 0.9 percent higher than the three-year average of 3.6 million pounds. Total YTD imports were down 10.9 percent from 2017, where Mexico (-37.8%), Brazil (-29.1%), Ecuador (-19.7%), Costa Rica (-14.1%) and Colombia (-10.6%) all saw declines in imports for the month of November. Fresh Tilapia Fillet Pricing From a replacement cost basis, as well as the adjustments to the weighted import price per pound (which includes only the top five suppliers) we found that the November figure of $2.55 fell $0.07 per pound from the previous month and $0.39 from Septemberâ&#x20AC;&#x2122;s record high of $2.94. Imports of Frozen Tilapia Fillets Imports totaled 25.5 million pounds for the month of November, up 27.7 percent from the previous month. YTD imports were down 3.2 percent compared to 2017. Compared to the previous three-year average, however, November imports were 9.3 higher than the average. Frozen Tilapia Fillet Pricing Replacement prices fell $0.01 to $1.66 per pound for the month of November. The accompanying charts try to illustrate the behavior of replacement costs (L) and U.S. wholesale prices (R), respectively. We must remember that when costs overseas advance, it is likely that U.S. importers will try to pass the increase onto the U.S. market.

Cost Behavior (Arrival) 2016



Imp. $/lb

$2.00 $1.95 $1.90 $1.85 $/lb.

$1.80 $1.75 $1.70 $1.65 $1.60 Jan












3-5 oz. Fz. Fillet 2017



16-´18 avg.

$2.05 $2.00 $1.95 $1.90 $/lb.

Imports of Whole Fish Tilapia Imports of frozen whole fish were up 43 percent from the previous month, registering 9.7 million pounds in November 2018. Imports were up 11 percent on a YTD basis. Compared to the previous three -year average of 7.5 million pounds for the month of November, November 2018 was 29.3 percent higher than the average.

$1.85 $1.80 $1.75 $1.70 Jan






Three-year average pricing from 2015-2017 steadily declined after record high prices in 2014. Since then, imports trended lower and prices remained steady at approximately $1.80 in the U.S. wholesale market until recently, where demand started picking back up and prices began strengthening ahead of the tariffs. With falling replacement costs and slightly increased wholesale prices, the ratio of these two numbers continued to increase from 1.21 to 1.24. Wholesale prices steadily strengthened, reaching an average of $2.05 per pound.

Frozen Analysis & Other inputs YTD weighted replacement costs were at their lowest level since 2007,







registering $1.71 for the month of November with import volume falling year-over-year since 2014. Price quotations were continuing to strengthen on product from China as 10 percent tariffs went into effect. Increased shipments were scheduled to arrive prior to the latest tariff negotiating deadline.

Domestic Channel Catfish, Urner Barry Prices Domestic catfish supplies and demand remained well balanced. Volume deals on excess inventories seemed to be dwindling. Domestic fillet prices were steady with a strengthening undertone. 1


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U.S. Imports All Types, By Type The release of this report was delayed due to the 35- day government shutdown, but we now know that November imports of warmwater shrimp products were 5.2 percent higher than in November 2017. The year-todate total was 1.396 billion pounds, 4.8 percent higher than the Jan-Nov 2017 total. India (+11.5%), Indonesia (+7.7%), Vietnam (+33.2%) and China (+26.6%) all shipped more shrimp to the U.S. in the month of November when compared to the same month one year earlier; meanwhile, Ecuador (-0.8%), Thailand (-24.4%) and Mexico (-3.2%) shipped less. Monthly Import Cycles By Country (All Types) India: The U.S. imported 49.6 million pounds of shrimp from India in November (+11.5%) compared to 44.5 million in November 2017. The eleven month total was 16 percent more than the Jan-Nov 2017 total. India continued to be the dominant supplier to the U.S., accounting for roughly 36 percent of all shrimp imported into the country. Indonesia: Shipments from Indonesia were up for a second-straight month in November, increasing 7.7 percent or 1.9 million pounds. Imports from Indonesia were 13% higher year-to-date. Indonesia continued to be the second largest supplier of shrimp to the U.S. market, accounting for slightly more than 19 percent of all shrimp imported. Ecuador: Shipments from Ecuador to the U.S. were marginally lower in November, down 0.8 percent. Still, imports remained 6.4 percent higher year-to-date. 78 Âť

U.S. Seafood Imports - Shrimp, Total 2016



190 170

Million lbs.

150 130 110 90 70 50 Jan






Thailand and Vietnam: Shipments from Vietnam were 33.2 percent higher in November and 5.7% higher year-to-date. Thailand shipped 24.4 percent less for the month and 34.9% fewer for the year.

Value-Added, Peeled Shrimp Imports Imports of peeled and deveined shrimp increased 7.6% in the month of November, and the category grew by 7.6 percent or 43 million pounds year-to-date. The growth was solely driven by India, who increased their volume shipped by 55 million pounds or 21.3 percent through November. India (+16.8%), Indonesia (+4.7%), Ecuador (+19.6%) and Vietnam (+0.9%) all shipped more peeled shrimp in the month than in November of the prior year. Thailand (-29.2%) was the only significant supplier to ship less. When compared to the prior year, replacement values were 12.5 percent or $0.57 lower. Shrimp Price Timelines; Retail Ads Retail: According to our index, retailers were featuring shrimp at a greater rate than in any of the prior five years. When comparing featuring instances during the month of No-







vember, activity was up 20 percent while ad prices averaged $0.27 or 3.4 percent below the same month in the prior year. Total year-to-date buying opportunities were up roughly 36 thousand or 5.9 percent; and in terms of value, the price was 2.77 percent lower YTD. Buying opportunities were consistently higher and prices consistently lower for most of the year.

U.S. Shrimp Supply & Gulf Situation Wild, Gulf of Mexico: Market values were steady and the effort in the region had seasonally slowed while attention was turned more towards inventory management. The National Marine Fisheries Service reported November 2018 landings (all species, headless) of 8.207 million lbs. compared to 8.898 million in November 2017. The cumulative total stood at 89.971 million lbs.; 3.7 million pounds or four percent below the Jan-Nov 2017 total of 93.681 million lbs.



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aquaculture events OCTOBER AQUACULTURE EUROPE 2019 Oct. 8 – Oct. 10 Berlin, Germany T: +1 760 751 5005 E: worldaqua@aol.com W: www.was.org

JUNE WORLD AQUACULTURE 2020 Jun. 08 – Jun. 12 Singapur T: +1 760 751 5005 E: worldaqua@aol.com W: www.was.org

NOVEMBER 2nd INTERNATIONAL SYMPOSIUM ON MARICULTURE Nov. 7 – Nov. 8 Ensenada, Baja California, México T: + (210) 504 36 42 E: crm@dpinternationalinc.com W: www.aquaculturemag.com

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AQUACULTURE MAGAZINE April-May 2019 Vol 45 No.2  

Seeking the perfect oyster shell

AQUACULTURE MAGAZINE April-May 2019 Vol 45 No.2  

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