Size and structure of crayfish (Astacus astacus) populations on different habitats in Finland |
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Authors: | K Westman M Pursiainen |
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Institution: | (1) Fisheries Division, Finnish Game and Fisheries Research Institute, P.O. Box 193, SF-00131 Helsinki 13;(2) Evo Inland Fisheries and Aquaculture Research Station, 16970 Evo, Finland |
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Abstract: | The many inland waters in Finland make crayfish production an important potential resource. The rational utilization and management of this resource requires knowledge of the size and structure of the crayfish populations. The difficulties often encountered in catching crayfish complicate population studies. Mark-recapture and electric fishing have been used in the studies. The number of adult crayfish measuring more than 70 mm in a 4-ha lake was estimated at 620, and the number in a 13-ha lake at 3 480. In the lakes, the density of adult crayfish was around 0.6–1.4 m–2 and in one stream studied about 2.5 m–2 rising to several individuals per m2 in the best biotopes. |
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Keywords: | freshwater crayfish Astacus astacus population size population structure catching methods |
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