the interview Stefan Dullstein Stefan Dullstein is Head of Industrial Segment – Aquaculture at Linde Gases. Here, he is responsible for management of R&D studies, market analyses, introduction of new products and training and aquaculture team supervision. Stefan has been with Linde for more than 15 years working in various water treatment roles and, prior to that, worked in wastewater treatment and research for the Institute of Environmental Technology at the University of Bremen. He has an engineering degree from the University of Stuttgart and a PhD in dynamic simulation in waste water treatment from the University of Bremen. International Aquafeed magazine caught up with Mr Dullstein at Aquaculture UK recently, held this year at the Macdonald Aviemore Highland Resort, situated at the foot of the Cairngorm Mountains in Scotland.
Linde have many years of experience in the gas supply industry and have been long established as an international brand name. But who are Linde Gases and what is unique to the company that they are able to offer to the Aquaculture industry?
Linde Gases is an international gas company with more than 60,000 employees active in more than 100 countries, providing solutions for the gas industry and any other kind of application where you need gases, including aquaculture. So in the field of aquaculture we are developing solutions for the fish farming industry since the mid 1980’s. Linde undertakes the research and development of all our aquaculture technology at our Innovation Centre in Ålesund, Norway. With its highly equipped laboratories demonstration tanks, the Centre allows aquaculture technologists to observe how the latest oxygenation technologies impact farmed fish development. Since its opening in 2012 Linde has introduced the capability to run warm water trials to understand and assess the performance of its technology in high temperature water environments inhabited by more tropical species. Additionally, they have recently installed an external floating dock where technology trials can be performed in the surrounding fjord.
Are Linde currently developing any new aquaculture specific technologies, and if so, what are they and why is their function so important to the aquaculture industry?
The most important factor for achieving healthy fish is to have healthy water; thus, controlling the concentration of oxygen dissolved in water is crucial in aquaculture. Maintaining the right level of oxygen in water improves utilisation of feed, reduces fish mortality and reduces the need for antibiotics. The latest development that we are presenting here is the Solvox DropIn unit, which can be used for sea cages when you have low oxygen concentration. Naturally in sea cages, you would always have enough oxygen from the surrounding water, but there are certain scenarios where extra oxygen needs to be added to ensure the fish’s wellbeing.
Are Linde currently in a position to offer a unique solution to any of the major issues that currently face the aquaculture industry, such as sea lice?
Sea lice treatment is indeed one of the key applications of the Solvox DropIn unit. Sea lice are parasites well known to the aquaculture industry for posing a significant threat to fish farmers. They can compromise the health of fish, and damage their host’s skin through feeding, causing lesions
and infections through viruses and bacteria. Though they occur naturally in the marine environment, sea lice can represent a particular issue among farmed fish where a more concentrated population means that infestations can spread quickly. In the summer season in particular, low oxygen concentration results in farmers being unable to continue feeding as they would like. The impact of sea lice and resulting treatment also affects the need for additional oxygenation. In Norway, farmers start pulling skirts around their cages to prevent sea lice eggs getting into the cages or to give full cage coverage during sea lice treatment, which means that providing oxygen to the water is all the more important.
Are you aware of any of your competitors’ products, and have you shared their experiences of using them, how do you feel that the solutions that your competitors offer compares to the solutions offered by Linde?
We are aware that there are solutions on the market with perforated hoses, but feedback from our customers is that they provide poor handling. Based on this, we developed a solution that can simply be dropped in to the water. Solvox Dropin can be lowered into the water with a crane from a boat and is operational within 15 minutes. The booth here is not big enough for us to exhibit the entire Solvox package, which comprises the Solvox DropIn twin kit including two drop-in units together with automatic gas dosing, power connections for the pump and an optional oxygen probe fully integrated into the unit. The probe allows the user to easily gauge that there is the right concentration of oxygen within the cage.
When do you believe that this new product will be made available and which markets will it be launched in? Also, have Linde had the opportunity to test the product yet?
The product will be available worldwide. We have run trials in Norway and Tasmania to test it during summer season, allowing us to hold trials every six months. We are first going to launch in these geographies and anticipate a global rollout later in the year.
Other than Aquaculture UK, do you exhibit your products at any other shows?
We have also exhibited at Aquanor in Norway and look forward to showing the product at more global shows as the year goes on.
74 | July | August 2016 - International Aquafeed