Burbot, the new finfish species for coldwater aquaculture

European Network for the Dissemination of Aquaculture RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. : TL2003-198

Burbot (Lota lota) is the freshwater cousin of cod. The meat of this finfish is tasty and nutritious. In some parts of Europe, burbot liver is a delicacy and a few centuries ago, it was considered as a “royal” meal. At present, this species is endangered in many European countries; hence there is much interest in the development of restoration programmes and aquaculture.

Burbot can easily spawn in captivity, but spawning is usually asynchronous and this can present problems for further culture, from egg incubation to larval rearing. Sometimes, the eggs from spontaneous spawning may be collected over a period of one month or more. Hormonal spawning agents: hCG (human chorionic gonadotropin), CPE (carp pituitary extract) and GnRHa with dopamine antagonist, were tested to try to achieve spawning synchronization. All of the tested agents worked well, but the best results were obtained after applying hCG and GnRHa. The spawning time was synchronous and fish spawned between 4 and 7 days after hormonal treatment.

Burbot eggs are small (about 1mm diameter) and semi-floating. Incubation was carried out in Weiss jars at temperatures below 4°C. Water flow rates through the incubation jars had to be low. When the embryos (still in the egg) show pigmentation, the water temperature may be increased to 6°C, and later to 8-10°C during hatching.

Burbot embryos and larvae are similar to those of marine finfish or to percids larvae. Initially, the main problem is swim bladder inflation, which may influence larvae survival. Conditions used were similar to those used for perch culture. Normally, there are no problems with first feeding. Burbot larvae have a large mouth, so they can eat i.e. Artemia naupli. The addition of other live food, such as rotifers, increased survival of the larvae. After a few weeks of rearing, the larvae may be progressively weaned onto dry feeds - the best results being obtained using dry feeds for cod. The optimum rearing temperature is about 12°C at the beginning of rearing, increasing to 15-20°C after a few weeks. One of the biggest problems in burbot larvae culture is cannibalism. Larvae of 8mm length can eat others that are only 2mm shorter! This may therefore present a real problem in mass culture. One of the ways of decreasing cannibalistic attacks is to offer primary live food ad libitum. Later, when the fish have reached a total length of 12-15mm, other foods than Artemia must be given, such as dry feeds for cod. However, when feed is not given in sufficient quantity, cannibalism occurs, most notably during feeding or shortly after switching on the light. Some fish are observed to be interested in the feeds offered; others are more interested in other larvae.

The results obtained from this and other pilot projects show the potential for burbot culture. Its high growth rate, tasty meat and high market price are motivating factors involved to start full-scale culture of this species.

For more information, contact:

Prof. Andrzej Mamcarz
Department of Lake and River Fisheries
Warmia and Mazury University in Olsztyn
Poland
Tel.: (+48 89) 5233388
Fax: (+48 89) 5233969
E-mail: mamcarz@uwm.edu.pl

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