Pikeperch, perch and pike in the sea area Pikeperch (Sander lucioperca), perch (Perca fluviatilis) and pike (Esox lucius) are important species of the catch in Finnish coastal areas. Ways of improving the preconditions for professional fishing of these species are being studied in a follow-up study on stock abundances.
Under the programme, the development of pikeperch, perch and pike stocks are being monitored, and the effects of fishing inventoried. The findings are being used in the management of fish stocks and in assessing the need for fishing regulations.
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At the moment, perch catches are abundant. Photo: Ari Saura |
Results
The perch and pikeperch catches of professional fishermen doubled from the middle of the 1980s to the end of the 1990s. Since then, catches have varied annually, without any distinct trend. Perch and pikeperch in Finland have benefited from the recent warm summers. Pikeperch and perch reach minimum catch size in 5-6 years, and a strong year class may affect the catches for up to 10 years. Pike catches have been relatively stable since the 1980s.
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| Commercial catches of perch, pikeperch and pike off the Finnish coast in 1980–2007. |
The grey seal stock is strengthening quickly and making gill net fishing more difficult in open water season. In some areas, fishing has ended altogether. Seals may eventually change the behaviour and migrations of fish, causing the traditional methods of fishing to fail, as 95% of the pikeperch catch and two thirds of the perch catch are currently caught with gill nets. Seals have also spread to the inner bays.
The number of cormorants has increased rapidly during the past few years. Strong cormorant stocks may affect the number of pikeperch and perch recruits. The issue is being studied in cooperation with the Finnish Environment Institute.
Pikeperch spawning grounds and larval areas can be found in dim and eutrophic bay waters. The occurrence of larvae is currently being monitored in the VELMU programme.
Current issues
Samples of about 5,000 fish from the pikeperch and perch catches of professional fishermen are collected annually in the EU data collection programme. Length, weight, age, sex and stage of maturity are determined, and the changes in the age structure and growth rate of the stocks are monitored using these data.
The success of stocked pikeperch is studied in a separate project. The structure of coastal fish communities is monitored with experimental fishing. Data on the catches of professional fishermen are also collected when compiling statistics.
Scientist in charge of project
Heikki Auvinen
Finnish Game and Fisheries Research Institute
Turku Game and Fisheries Research
Itäinen Pitkäkatu 3, 20520 Turku, Finland
Tel. +358 - (0)205 751 695, fax +358 - (0)205 751 689
e-mail: firstname.lastname@rktl.fi
Other research staff: Jari Raitaniemi
Duration: continuous
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