Comparative Analysis of the Concentrations of Ions (Na+, K+, Ca2+, and Cl‒) in the Blood of the Brown Trout Salmo trutta from Different Rivers

Resumo

The contents of ions in the blood have been compared in three ecological groups of brown trout (parr, mature, and resident) living in rives of the basins of Lake Onega and Lake Ladoga. Brown trout from the Alats-oya (the Ladoga basin, remote from two other rivers belonging to the Onega Lake) is characterized by the lowest concentrations of the Na⁺, Ca2⁺, and Cl^– ions in blood. The probable effect of the ion level in blood of brown trout on selection of life strategy is discussed.