According to the FAO, the production of food from marine, freshwater, and brackish water has altered from being predominantly based on capture fisheries to the culture of farmed species. At the global level, 2014 was the first year when farmed production of species for human consumption exceeded output of wild catches. In Europe, aquaculture production has for many years not grown at the same pace as it has in the world as a whole. A variety of factors have contributed to this, including a lack of sites to expand, environmental restrictions, and bureaucracy. However, as it becomes increasingly apparent that fish farming is the only way to ensure the future supply of fish, policy in Europe is being designed to encourage this activity.
Recirculation systems reduce the impact of fish farming on the environment
One way of getting around stringent European environmental laws is to produce fish with little impact on the surroundings. Isolating production in this way is possible with the use of recirculation aquaculture systems (RAS). These recycle the water in which the fish are bred after passing it through a series of filters, while the sludge created by the fish excretions and excess feed is treated and then can be used as manure. In Lithuania these systems have proliferated thanks in part to subsidies from European structural and investment funds and today there are between 20 and 30 facilities in operation. RAS are typically more expensive than traditional ponds or raceways and are therefore typically used to cultivate high-value species such as sturgeon, trout, eel, turbot, and even shrimp. One Lithuanian company, JFish, is using this technology to breed African catfish (Clarias gariepinus), a meaty, fast-growing species. Giedrius Morkevicius, the technical director, says the choice of catfish was also determined by the fact that the company wanted a fish that was not otherwise being grown in the country.
The company started production in 2012 and has been selling the fish for the last three years. The fish reaches market size in 18 months and prefers higher water temperatures than for example the European catfish (Silurus glanis). The company runs a full cycle breeding programme – from broodstock to eggs, larvae, fingerlings, and adults. The first batch of broodstock was obtained from the Netherlands, where there is a longer history of breeding African catfish.
Tropical fish require tropical conditions
As a native of tropical climates African catfish require high water temperatures in order to thrive. At JFish the water for the RAS is obtained from the ground and warmed to the requisite temperature of about 22 degrees by pumping heated air through it and 5 to 10% of the water is replaced every 24 hours. The female broodstock are given an injection to induce spawning while the males are slaughtered and the sperm removed and mixed with the eggs to fertilise them. The females take about 9 months to recover from the spawning process. The fertilised eggs are kept in incubators for the first two months until they reach about 10 g in weight and are then moved to small tanks, where the temperature is maintained at 24-26 degrees C. In summer, however, precautions must be taken to endure that the environment does not become too warm. The fish are grown to about 1.5 kg, but the company also grows fish to larger sizes. At least twice during 18 months the fish are graded by size so that similar sized fish are grouped together. This is important to restrict cannibalism and to ensure that fish grow at more or less the same rate. In addition to temperature, noise levels must also be considered as African catfish are highly sensitive to sound and one must be careful not to touch the tanks in which they grow as this transmits a sound and stresses the fish. The lighting is also kept at a constant low level rather than being switched on and off, as these noises too can disturb the fish. Before slaughtering the fish are removed to harvesting tanks, smaller tanks with fresh water, where they are kept without feed for 24 hours to cleanse their guts. In these tanks the water is changed at least once a day, and more often when the density is higher to ensure that the fish do not have any off taste.
Vingio g. 13
54317 Kauno r.
Technical Director: Giedrius Morkevicius
Production: 30 tonnes per year
Products: Fresh fish, processed products
Establishing a restaurant to promote catfish consumption
The company has a production of some 30 tonnes a year which is then sold either fresh on ice or after being processed, such as smoked, at their own processing facility. Fingerlings are also sold to other Lithuanian fish farmers, who are using RAS, and JFish will buy back the market-sized product if there is a need. Mr Morkevicius estimates the total market for catfish in Lithuania to be around 100 tonnes, a figure he would naturally like to see increased. To this end the company has opened an upmarket restaurant at the production site, some twenty minutes by car from Kaunas, that serves only its own, freshly caught catfish prepared in different ways. The idea is to familiarise customers with the fish and to show them how it can be cooked to highlight the texture of the flesh and to optimise the taste. With its trendy design the restaurant is an effort to attract young people to catfish. Sales are currently only within Lithuania. However, the company is exploring export markets, but is aware that production of the smoked products, for example, will have to increase to at least a tonne a week before selling abroad is realistic. Catfish meat is lean and the smoked product is somewhat similar to ham. Today, the company itself processes most of its production, and 50% of this volume is sold through its own shop, while the rest goes through the retail chains. Hotels and restaurants are another potential group of customers, but the logistics of supplying them are more demanding, says Mr Morkevicius, who wants first to manage the competition from other suppliers (and from the black market) before embarking on an expansion of sales.
JFish has also been very open to the public about its activities and the technology it uses, sharing its experiences with other producers and inviting students to come and train as interns. This transparency was, however, not always the way the company interacted with the rest of the industry. In the beginning, Mr Morkevicius admits, JFish was more secretive, but as recirculation systems became more widespread and short films about running them started appearing on video-sharing sites, it became obvious that nothing could be gained from secrecy and perhaps greater openness would be better public relations. Ultimately, any initiatives that can contribute to popularising African catfish can only help the company in the long run.