Feeding of fish in Lake Glubokoe |
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Authors: | O S Boikova |
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Institution: | (1) A. N. Severtsov Institute of Evolutionary Morphology and Ecology of Animals, USSR Academy of Sciences, Leninsky Prospect 33, 117071 Moscow, USSR |
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Abstract: | Lake Glubokoe is inhabited by 13 species of fish. The commonest are roach, bream, perch and ruff. Comparison of seine catches
for 1950 and 1984 revealed a considerable decrease in the share of perch (from 31% to 2%) and ruff (from 18.5 to less than
0.1%) in 1984.
The richest food resource in the lake is crustacean plankton. In summer, it is mostly consumed by roach. Estimation of the
electivity shows that, unlike perch, roach selectively consumes small crustaceans (Bosmina and Polyphemus). Poor growth rate of all common species of fish points to their food limitation.
In summer the diets of common species of fish are differentiated to a considerable extent. Of 36 pairs of combinations a high
food overlap was found only in 2 cases: 1) O + perch and Leucaspius delineatus, 2) yearlings and adult roach. Low diet overlap in fish during intensive feeding in summer probably reflects a feedback between
the volume and intensity of food competition. The populations of bream and ruff probably compete for chironomid larvae which
inhabit the sublittoral, as perch, roach and Leucaspius delineatus probably do for large littoral insects. However, intraspecific competition appears to be more important than interspecific
for the roach and bream populations (the two most numerous species in the lake). |
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Keywords: | food composition lake fishes food resources fish growth rate diet overlap food competition Lake Glubokoe |
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