Age, growth rate, and condition of vendace, Coregonus albula (L.), from some Pomeranian Lakes (NW Poland)

Kazimierza Królewicza 4, 71-550 Szczecin, Poland, phone: (+4891) 4231061 ext. 330, e-mail: zgl@fish.ar.szczecin.pl INTRODUCTION The vendace, Coregonus albula (L.), is one of the most valuable fish species caught in Polish lakes. The factors contributing to its high value are: high quality meat, fast growth rate, shoaling behaviour, and high market value. These qualities explain why, despite the high environmental requirements of this species, its catch had been increasing systematically in Poland, in the 1980s, reaching almost 600 t per year. However, due to the transformation of the fishing industry, the vendace fishery decreased twofold in the 1990s (Leopold and Wo3os 1999). The disappearance of Coregonus sp. in lakes has also been related to adverse changes resulting from . Vendace are found in 44 out of 1575 lakes of Polish western Pomerania (Filipiak and Raczyñski 2000), although only 23 of them are explored by professional fishermen (Czerniejewski and Filipiak 2001). Unfortunately, due to a lack of knowledge on the biological features of vendace populations inhabiting these waters it is impossible, in many cases, to implement a reasonable fisheries management. We decided to focus our attention on three, hitherto not studied, vendace populations inhabiting lakes Pe3cz Wielki, Bytyñ Wielki and We3tyñ (Table 1) and to determine the biological features of those fish, in particular their age structure, growth rate, and condition.