ANNUAL OVARIAN CYCLE OF VIMBA VIMBA (L.) FROM THE DRAWIEŃSKI NATIONAL PARK IN NORTHWEST POLAND
Piotr Hliwa, Krystyna Demska-Zakęś, Andrzej Martyniak
University of Warmia and Mazury in Olsztyn, Poland
ABSTRACT. Macroscopic and microscopic changes which occur during the annual ovarian cycle of vimba females from the Drawieński National Park (DNP) were studied. The study was carried out in 1997-1998 using 146 fish with an average body length (longitudo corporis) of 24.2 cm and an average body weight of 274.9 g. No abnormalities or pathological changes in the ovaries of the investigated fish were detected. The histological picture showed the clear asynchronicity of oocyte maturation. The following ovary maturity stages, characteristic for portion spawners, were distinguished: IV2; V2; IV3; V3. A relatively short post-spawning stage was also identified (VI/II). It was confirmed that in vimba from the Drawieński National Park (DNP) the longest the maturity stage is III, which starts in October and finishes in March or April of the next year.
Key words: VIMBA VIMBA, OVARIAN CYCLE, GONADOSOMATIC INDEX
Piotr Hliwa, Uniwersytet Warmińsko-Mazurski, Zakład Genetyki Ewolucyjnej, ul. Oczapowskiego 5, 10-957 Olsztyn, Tel./Fax:+48 89 5234787; e-mail:email@example.com