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EXPERT TOPIC CATFISH

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Introduction by Alex Whitebrook

CATFISH EXPERT TOPIC

The North African catfish (Clarias gariepinus), despite its name, is common across much of Africa, the Middle East and Eastern Europe. This impressively diverse distribution gives this species the widest latitudinal range of any freshwater fish in the world. Beyond its natural environment, the fish has been used extensively for aquaculture purposes across the world. The species is an opportunistic and omnivorous predator, having the ability to efficiently switch between food sources depending on availability. Reflecting its eating habits, the catfish is equipped with a wide, sub terminal and transverse mouth capable of eating a variety of food organisms ranging from phytoplankton to fish. Of course, the ability of the North African catfish to digest most feed ingredients used in aquaculture, in turn favours a high rate of translocation. To date, the fish has been translocated to 23 African countries, four European countries, 10 in Asia and one in South America, where it is or was used for aquaculture purposes; however, catfish production is primarily focused within three countries: Nigeria (79%), the Netherlands (9%), and Hungary (4%). Depending on the location, the species is produced using different farming systems, with no uniform or best-practice methodology yet established. Thanks to its euryphagic nature and environmental flexibility, the feed formulation used to grow the species utilises a wide

variety of ingredients, and in some cases is used to manage farm biowaste. Feeds used to produce this fish include dry feeds ranging from single ingredient dry feeds such as maize bran, to farm-made feeds, to formulated floating or slow-sinking, extruded feeds, as well as single ingredient or mixed moist, farm-made feeds. In many African countries, the North African catfish is an important foodfish, but the high cost of formulated commercial fish feeds is a major constraint to the expansion and growth of the aquaculture sector. In this month’s edition of expert topic, it is precisely this issue that our author addresses. The catfish industry has had great success in recent years, producing upwards of 48, 000 tonnes, but the industry is constrained by the lack of affordable, high quality feeds. In the search to find alternative, cheaper methods and tackle the sporadic supply of good feeds to Nigerian farmers, Aller Aqua has approached the market with care and attention to local requirements. The article follows the story and methods of Aller Aqua in its attempt to sufficiently supply the largest North African catfish market in the world.

32 | April 2017 - International Aquafeed

APR 2017 - International Aquafeed magazine