Morphology of the Eurasian perch (Perca fluviatilis L.) from two different localities of the Danube basin in Serbia I: similarities and differences of juveniles

Abstract

The morphology of juveniles of the Eurasian perch Perca fluviatilis L. from two different localities, both belonging to the Danube basin in Northern Serbia, were studied by means of different statistical methods. Samples were taken monthly, from June through September of 1988, 1989 and 1991, revealed a different mode of growth, and consequent significant morphological differences between juveniles of different age from same sampling site and within the same age classes from different sampling sites. These differences are especially prominent in the first months of life, and tend to diminish completely toward the end of the first year. These differences could be explained by different ecological conditions between two sampling sites, especially in the availability of different food types and different temperature and oxygen regimes.