Biology of resident Dolly Varden trout Salvelinus malma (Salmonidae) from a river with increased natural concentration of toxicants and suspension (Eastern volcanic belt of Kamchatka)

Abstract

Specific biological features of the population of resident Dolly Varden trout Salvelinus malma inhabiting upper reaches of the Falshivaya River whose water in mean water period has natural increased concentration of copper (0.006–0.018 mg/L), zinc (0.061–0.072 mg/L), and suspension (6–8 mg/L) are described. Its spawning was recorded in mouths of tributaries where (unlike the main river) water is not toxic, its mineralization is two times lower, and turbidity does not exceed 1 mg/L. Among juveniles that left the ground, individuals with scoliosis (11%), undeveloped fins (16%), and exophthalmia occur. The numbers of the population are maintained due to early maturation and spawning before the accumulation in the body of a lethal dose of toxicants and critical amount of functional disturbances. In prespawning fish (3+), multiple pathologies of the histological structure of the gills, liver, and spleen up to necroses were recorded. On average, 10% of maturing oocytes in the ovaries are at different stages of apoptosis. The frequency of pathologies correlates with the concentration in the liver of copper, zinc, and sulphur whose concentration significantly increases with an increase in body weight.