European whitefish helps Finland’s trout farmers diversify

Until the 1990s consumer demand for farmed fish in Finland was satisfied by the country’s rainbow trout farms but subsequently globalisation of the fish market which increased salmonid imports resulted in rainbow trout prices falling and reduced profitability for Finland’s trout farmers. “As rainbow trout lost its luxury image consumers’ interest in other fish species increased despite their higher market price,” said Juha Koskela of the Finnish Game and Fisheries Research Institute based at Jyväskylä. In 2004 the price of farmed European whitefish in Finland was almost double that of farmed rainbow trout.

To help trout farmers develop new species the Institute carried out feasibility studies to evaluate the market and cultivation potential of different native species to select the best potential candidates for further study and eventual commercial production. “From our analysis European whitefish (Coregonus lavaretus L.) was considered to have the best potential for diversification since it has several advantages over other species we looked at which included pike perch, perch and arctic char,” said Juha Koskela, who is leading the research.

These advantages included the fact that seed material was already available as European whitefish brook stock was already in cultivation and that larvae could be grown successfully using commercial dry feeds developed for marine species. In addition European whitefish grow well in the temperature conditions common in Finland’s lakes and brackish water courses.

Found in the wild in fresh and brackish water in most European countries European whitefish, a member of the salmonid family, was already a known and valued species in Finland where 1,200 tonnes were caught annually by professional fishermen. “Its white flesh is a good alternative to red fleshed salmon and the initiation of farming is not as difficult as for other new species since the production methods used for rainbow trout are partially suitable for European whitefish. In addition, brood stocks of several whitefish strains have been farmed for several decades for restocking purpose lakes and the Baltic Sea and these stocks provide eggs for use in fish farming for commercial food fish production,” said Dr Koskela.

While whitefish farming for restocking was usually done semi-intensively in ponds with annual production between 22-25 million juveniles, commercial food fish farming is based on intensive farming.

During their first year European whitefish are reared in indoor plastic tanks in fresh water with a flow-through system and under natural temperature conditions. Following the juvenile phase net cages and earth tanks are used, again under natural temperatures. The production cycle, from larvae to market size, which is around 600g, takes 18-28 months. “The reason for the long production cycle in Finland is the naturally low temperatures during winter which is a five to six month period. During that time water temperatures are usually around 1-3°C and growth is extremely slow,” said Dr Koskela.

However the production period can be reduced to an 18 month cycle if heated water is used during the egg incubation stage to accelerate hatching as well as during the juvenile phase.

“Although the farming technology used for rainbow trout can be partially transferred to European whitefish production there exist certain differences in rearing methods especially during the egg and larvae stage and to some extent in the feeding, nutrition and handling of the growing fish,” said Juha Koskela.

Diversification project, which began in the mid 1990s, aims to develop a profitable production procedure for the cultivation of whitefish by improving its growth rate, welfare and flesh quality as well as reducing feed costs. During the past 10 years research has focused on solving biological production problems concerned mainly with feeding, nutrition, growth and welfare with research carried out mostly in laboratory scale.

“After we became familiar with the rearing biology of this species the work developing net cage rearing techniques for brackish water environment began,” said Juha Koskela. “This five year long project was carried out in cooperation with private enterprises to ensure direct transfer of rearing technology to the end users.”

One target of the initial research stages was to develop an optimal growing diet for European whitefish and the Finnish fish feed company Raisio Feed Ltd has used the results obtained to produce species-specific feed.

Currently Dr Koskela and his team are working on a selective breeding programme for European whitefish together with genetics and economic researchers with the aim of measuring heritability and the economic importance of different production and quality traits in order to produce an optimal family-based breeding programme. There is also a three year research programme to improve whitefish flesh quality which is planned to start later this year.

So far the transfer of technology to the industry has resulted in commercial production reaching around 430 tonnes in 2004 which was expected to double in 2005, produced by around 20 farmers who are farming European whitefish alongside rainbow trout. “Today farmed European whitefish is supplied to the Finnish fish market all year round. With growing production farmers are now interested in exporting it to European markets and therefore farmed European whitefish products will be on show at the European Seafood Show at Brussels in May,” said Dr Koskela.

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