The growth of pikeperch (Sander lucioperca L.) and perch (Perca fluviatilis L.) under different water temperature and salinity conditions in the Curonian Lagoon and Lithuanian coastal waters of the Baltic Sea

Pikeperch and perch perform seasonal migrations between the Curonian Lagoon and the coastal waters of the Baltic Sea. The Curonian Lagoon is a freshwater basin, while salinity in the coastal waters varies between of 4.9-6.8 psu. In the Curonian Lagoon water temperature is generally higher than in the coastal waters. Field studies of growth and condition characteristics of pikeperch and perch were carried out in these water bodies with the aim to estimate growth differences of the two fish species under different salinity and temperature conditions. Additionally, an experimental study of the impact of salinity on the growth of perch young-of-the-year (YOY) was performed to test the hypothesis that a brackish environment positively influences percids. Field observations revealed that body length, condition factor, fatness coefficient and fat content in muscles were significantly higher in individuals inhabiting the cooler, brackish waters of the Baltic Sea than in individuals inhabiting the Curonian Lagoon. A positive effect of low salinity on growth was also established in the experimental study. Hence, the study results suggest that under certain temperature conditions, brackish waters beneficially affect the growth of pikeperch and perch.