PIKEPERCH (SANDER LUCIOPERCA (L.)) EXPLOITATIONIN REFERENCE TO STOCKING PROGRAMS AND THE SIZE STRUCTURE OF ITS HABITATS IN NORTHEASTERN POLAND IN 1951-1994
Andrzej Skrzypczak, Andrzej Mamcarz
Department of Lake and River Fisheries, University of Warmia and Mazury in Olsztyn, Poland
ABSTRACT. The analyses were based on commercial fisheries records of catches and stocking in lakes in northeastern Poland. The authors described the lake size structure in three categories of pikeperch, Sander lucioperca (L.), habitats determined by the frequency of occurrence of this species in commercial catches. In each of the five lake size classes, the moment pikeperch individuals appeared was pinpointed in light of stocking programs. Differences in the value of pikeperch exploitation parameters were determined in the three habitat types, and the level of variation was examined in stocked and unstocked lakes. Trend lines of pikeperch exploitation in the 1951-1994 period were plotted for these groups of lakes. The importance of pikeperch stocking for the occurrence of this species in new habitats declined as the size of the studied lakes increased.
Key words: PIKEPERCH (SANDER LUCIOPERCA), HABITAT, LAKES, STOCKING, RELATIVE CATCH
CORRESPONDING AUTHOR:
Dr Andrzej Skrzypczak, Uniwersytet Warmińsko-Mazurski, Katedra Rybactwa Jeziorowego i Rzecznego, ul. Oczapowskiego 5, 10-957 Olsztyn, Tel.: +48 89 5233388;
e-mail: andrzej.skrzypczak@uwm.edu.pl