EVALUATION OF THE RIVERS VILNIA AND SIESARTIS ECOTOXICOLOGICAL STATE BASED ON MORPHOLOGICAL INDEXES OF JUVENILE ATLANTIC SALMON (SALMO SALAR L.) / SIESARTIES IR VILNIOS UPIŲ EKOTOKSIKOLOGINĖS BŪKLĖS ĮVERTINIMAS PAGAL ATLANTINĖS LAŠIŠOS (SALMO SALAR L.) JAUNIKLIŲ MORFOLOGINIUS RODIKLIUS

Objective of the study – to evaluate ecotoxicological state of two probably differently polluted salmon rivers: the Vilnia and Siesartis based on Atlantic salmon (Salmo salar L.) juvenile’s morphological indexes. Statistical analysis of estimated fish morphometric parameters and morphological indexes showed that the Vilnia and Siesartis Rivers’ salmon juveniles differ significantly. Condition factor (CF) and the gills-somatic index (GSI) were found to be the most sensitive biomarkers reflecting the physiological state of the fish. The Vilnia River salmon juvenile CF and GSI value was significantly different as compared with the Siesartis River’s salmon juvenile indexes, apparently, due to the increased water pollution. Since according to the classical physico-chemical parameters, both rivers’ water was very similar [no significant differences were found (p > 0.1)], it was suggested that here exist other non-specific chemical factors (pollutants) in water, which determine fish physiological and indicate river ecotoxicological states