Kazimierz Wieski
Agricultural University of Szczecin, Królewicza 4, Szczecin, Poland

Key words: fat, protein, growth, roach, fish bioenergetics, estuary.

Abstract. The chemical body composition of roach (Rutilus rutilus L.) from four areas of the Odra River estuary was investigated based on a sample of 132 fishes. Growth rate was analysed using a sample of 738 individuals. Larger fish were prone to more intense fat accumulation. Fat content increased as the growing season progressed, especially in the fish inhabiting coastal Baltic waters and the eutrophic Lake D�bie. Dry matter content exhibited a similar tendency. The protein content did not change essentially, and although it did not depend on fish size in the post-spawning period, it increased slightly with fish size in autumn. Ash content was not correlated with fish size. The fastest length growth rate was observed in fish from the Pomeranian Bay, while the slowest occurred in roach inhabiting Międzyodrze.