The effect of temperature on condition, fecundity, and egg quality of vendace, Coregonus albula L

Abstract

Long-term observations showed a relationship between egg quality, vendace fecundity, and thermal conditions in the vegetation season. In warm years (eg. 1983) fecundity was higher than in cold years (eg. 1984). Egg quality showed an opposite responce: dry weight and calorific value were lower in warmer years than in colder ones. It seems that the increase of fecundity takes place at the expence of egg quality, and the worse the egg quality, the weaker the progeny. Hence, it can be assumed that this is one of the self-regulatory mechanisms controlling stock density.