Effects of eutrophication on vendace, Coregonus albula (L.). III. Seasonal morphological variability of vendace from selected lakes in Wielkopolska

The aim of the study was to determine and compare the most important morphometric and meristic characters of vendace from four lakes located in the Wielkopolska region: lakes Dominickie, Gorzyńskie, Lubikowskie, and Strzeszyńskie. Biometric analyses were conducted based on the method developed by Prawdin. All morphometric characters are presented in relative values (%) of fork length (longitudo caudalis) according to the method developed by Smitt. Moreover, values of 14 meristic characters were also determined. The greatest differences in values of morphometric characters of vendace were recorded for measurements of head shape, including lateral head length, eye diameter, and postorbital distance, and adipose fin length. The smallest differences in the values of morphometric characters were observed in the largest linear body measurements, i.e., body length, predorsal distance, minimum body depth, and dorsal and anal fin lengths. Variation in morphometric characters in vendace from different lakes confirms the hypothesis that a specific form of vendace is found in each lake. Differences were found in the values of linear measurements of vendace caught in different seasons, which indicates that drawing conclusions on body conformation in vendace is justified only when they are caught in comparable periods of the year.