New facility to produce 1,000 tonnes by next year

African catfish farming has gained considerable attention and success in Eastern Europe in recent years. The introduction of this nonnative species, specifically, the African sharptooth catfish (Clarias gariepinus), has opened new avenues for aquaculture in the region.

The African cat sh is highly adaptable to di erent water conditions and exhibits rapid growth rates, making it well-suited for aquaculture. Its ability to tolerate a wide range of temperatures and water qualities has made it an attractive option for. Additionally, the cat sh has a robust feeding behaviour and can consume various feed types, including commercial pellets and locally available organic matter, reducing production costs.

Cat sh farming typically takes place in specially designed aquaculture facilities such as ponds, tanks, or recirculating systems. ese systems provide optimal water quality, temperature, and oxygen levels, ensuring the healthy growth and development of the cat sh. Farmers closely monitor the environmental parameters to maintain the ideal conditions for the sh. e sh has gained in popularity in Central and Eastern Europe due to its market value. It is highly regarded for its rm esh and mild avour which appeals to consumers. Catsh llets are versatile and can be used in various culinary preparations, further increasing demand for them in the market. Furthermore, African cat sh farming has provided economic opportunities by attracting investments and creating employment opportunities, particularly in rural areas where alternative sources of income may be limited. e establishment of cat sh farms has stimulated local economies, contributing to the overall development of the region.

Juvenile output to increase by a factor of 12 e rapid growth, ability to tolerate high densities, and relative ease of culture have made the African cat sh a popular sh to farm in Lithuania. Production has increased steeply from 46 tonnes in 2014 to 893 tonnes in 2022, according to the Lithuanian Agricultural Data Center. Among the farmers producing this species is Vladas Vickūnas, the managing director of Akvapona. Mr Vickūnas has been farming cat sh for over a decade and has seen demand increase rapidly over the last couple of years. As a result, from 100,000 juveniles per year he now plans to grow out 1.2 million. is vast expansion has called for the construction of a new and larger facility which has been placed next to the older one on the production site in Skaisterių village just outside Vilnius. Inside the new building four larval tanks hold some 25,000 African cat sh larvae each. Between 20 and 40 of them will not survive here, says Mr Vickūnas, which is a reasonable mortality rate considering that in nature it would be about 99 that do not survive. Akvapona has its own broodstock for the production of eggs and sperm. e females are treated with hormones and then after about 12 hours the eggs are extracted. Depending on their size females can give up to 5 kg of eggs corresponding roughly to 5m in number. But for Akvapona’s purposes 800 g of eggs are enough, says Mr Vickūnas. Sperm is collected from the males with a syringe. Eggs can be harvested from the females every 3-6 months over a period of several years. e females currently used as broodstock are already 5-6 years old and some of them weigh more than 20 kg. But it is possible to use sh from the time they are a year old.

When cat sh farming rst started in Europe the original wild sh were brought from Africa. e wild sh were bred and subjected to selection for generations as the activity spread across the continent to create sh much more suited to being cultivated. Experience has taught Mr Vickūnas that the most eggs are produced when a male of Dutch origin is crossed with a female of Lithuanian or Latvian stock. e eggs hatch after 24 hours and the high fecundity means that the water in the tanks sometimes becomes opaque because of the larvae. e huge number of larvae brings its own challenges as it is more difcult to get the amount of feed right and not over- or underfeed.

African cat sh grow rapidly and are robust which has made them popular sh to farm in several countries.

For the rst 48 hours after hatching the larvae feed on the yolk sac, but thereafter they must be fed. Initially, Mr Vickūnas was using artemia, but then he found that a new feed developed by a Danish producer gave better results.

Despite being robust, African cat sh are sensitive

As the sh grow, they are graded and moved to larger tanks. Initially only a few sh are moved to make sure conditions in the new tanks are acceptable to the sh. If the initial group is thriving after three or four days then the rest of the batch is moved. In each batch about 1 are “shooters,” that is sh that grow many times faster than the others in the batch reaching 1.2 kg in the space of four months. ey are very aggressive and if they are not separated from their batchmates in time they will start to prey on them. Shooters can eat up to 40 of the smaller sh, says Mr Vickūnas, and must be placed in separate tanks within a few days of being identi ed. Although well known as a robust and fast-growing species African cat sh are also sensitive. Lights, sounds, and even scents can bother them. ey recognise people either from the timbre of their voices or, more likely, says

Mr Vickūnas, from their scent. Before the pandemic, the farm used to have groups of schoolchildren visiting, and Mr Vickūnas used to warn the accompanying teachers not to wear perfume as it disturbed the sh. ey are also not happy when the water is too clear. With high density and clear water, the sh can see each other and can start ghting. To prevent this a bit of sand and mud is mixed into the water to increase turbidity. When disturbed the sh dart around in the tank, while under normal circumstances the breeders will lie quietly at the bottom. As they grow the sh eat less and less as a proportion of their body weight. While the small ones put away 8 of their weight in feed, this fraction drops to less than 1 for the big sh.

Widespread use of technology

e move to the new site is not quite complete as some machinery is waiting to be installed including the grading equipment. is machine can automatically grade sh from 7 g and upwards sorting them into di erent containers depending on their weight category. Smaller sh however are graded manually. Other systems will measure the parameters of the water and the data can be monitored on a mobile phone app. e use of smart systems on the farm extend to the broodstock which have chips embedded in them. ese are injected with a pneumatic gun and encode data on the genetic provenance of the sh. is data can be accessed when the chip is scanned. is knowledge prevents undesired cross breeding and promotes desirable traits in the stock. e feeding system for the new tanks will also be upgraded to a pneumatic system that can scatter feed into the tanks so that all the sh can feed simultaneously. e old feeding system will be used instead in the hatchery. African cat sh require water at around 28 degrees so the water that is drawn from a well to feed the farm is heated by burning wood waste in winter and by heat pumps in summer. is year solar panels will be installed that will be used to heat the water though they will not cover more than 3 to 4 of the requirement in summer and nothing at all in winter. Mr Vickūnas is also experimenting with a bio oc in one of the sh tanks. is is the growth of benecial bacteria in the tanks that consume nitrogenous sh wastes and toxic metabolites and creating a protein-rich food source for the sh. Bacterial growth is fostered by maintaining a higher carbon to nitrogen ratio in the tank. e advantage of the bio oc is that the sh need less feed since they can feed on the bio oc. However,

Akvapona

Skaisterių str. 2C

Skaisterių village LT-13118 Vilniaus district Lithuania

Owner: Vladas Vickūnas

Activity: Catfish farming and processing the environment in a tank with a bio oc need to be carefully monitored to ensure that all the parameters are within healthy limits. However, he cautions, he is still learning about the bio oc, and will extend the experiment to some more small tanks and try it out for a year before deciding whether it is worth it.

Overseas buyers show interest

e sudden increase in demand and the need to expand the farm have a ected the company, which is running out of sh to sell. Fortunately, the summer is coming when demand is lower giving more space for the renovations and improvements. Next year capacity is expected to grow to 1,000 tonnes of which two-thirds will go to three big retail chains leaving some 300 tonnes for sale to smaller outlets such as shmongers and delicatessen shops including Akvapona’s own. We are also talking to potential buyers in other countries, says Mr Vickūnas, but I have deferred all commitments to after the New Year. e meaty taste of the sh makes it popular also in schools and kindergartens. And one of the most highly sought after products is cakes made from minced cat sh meat (70) and vegetables. Products like these are driving interest in sh among young and old alike and play an important role in a healthful and sustainable diet.

Volumes: 1,000 tonnes (2024)

Products: Headed fish, fillets with and without skin, portions, frozen fish cakes (14 varieties)

Markets: Lithuania

Customers: Supermarkets, fishmongers, delicatessen shops