GROWTH RATE AND HISTOLOGICAL PICTURE OF THE GONADS OF PIKE, ESOX LUCIUS L., AND PIKEPERCH, SANDER LUCIOPERCA (L.), FROM THE TRESNA RESERVOIR (LAKE ŻYWIECKIE)
Piotr Epler, Ewa Łuszczek-Trojnar, Magdalena Socha, Paweł Szczerbik, Mirosława Sokołowska-Mikołajczyk, Włodzimierz Popek
Department of Ichthyobiology and Fisheries, University of Agriculture in Kraków, Poland
ABSTRACT. The aim of this study was to determine the growth rates of pikeperch, Sander lucioperca (L.), and pike, Esox lucius L., from the Tresna Reservoir. Back-calculations were used to determine fish age. Histological pictures were used to determine the spawning success of the two species compared. The study material was comprised of 18 pikeperch females and 13 males, and 20 pike females and 12 males. The growth rate of pikeperch from the Tresna Reservoir was higher in comparison to populations inhabiting other basins in Poland. The histological analyses of the gonads indicated that pikeperch spawned successfully in the reservoir. The growth rate of the pike in the reservoir was comparable to that of this species in other basins. However, the histological picture of the ovaries indicated that spawning was only partially successful since 25% of females did not spawn and their eggs were in a state of resorption.
Key words: GROWTH RATE, GONAD HISTOLOGY, PIKEPERCH, PIKE
Piotr Epler, University of Agriculture in Krakow, Department of Ichthyobiology and Fisheries, Prof. Spiczakowa 6, 30-199 Kraków, Poland, Tel./Fax: +48 12 6375176, +48 12 6385979;