THE FEEDING OF SEXUALLY MATURE EUROPEAN PERCH (PERCA FLUVIATILIS L.) IN LAKE KORTOWSKIE IN THE AUTUMN-WINTER PERIOD
Bogdan Wziątek, Paweł Poczyczyński, Jacek Kozłowski, Kamil Wojnar
Department of Fish Biology and Culture, University of Warmia and Mazury in Olsztyn, Poland
ABSTRACT. This study addressed the feeding of sexually mature perch (Perca fluviatilis L.) in Lake Kortowskie in the autumn-winter period (October-March). A total of 81 perch specimens were caught, of which 20.2% were males, 69.1% females, and 7 specimens were of unidentified sex. The composition of the perch diet was very diversified. The food contained zooplankton, insect larvae, fish, and other components. Zooplankton was the most significant in late autumn (54.9% frequency of occurrence), whereas fish and insect larvae were found to dominate in winter. Differences in feeding were observed between the sexes (there was a lack of fish in the male diet) and between specimens of different length classes (specimens with lengths over 20 cm were obligatory predators).
Key words: EUROPEAN PERCH (PERCA FLUVIATILIS), FEEDING, LAKE KORTOWSKIE
Bogdan Wziątek, Uniwersytet Warmińsko-Mazurski, Katedra Biologii i Hodowli Ryb, ul. Oczapowskiego 5, 10-718 Olsztyn,
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