Experimental Assessment of the Chronic Effect of Increased Mineralization and Temperature on the Somatic Indices, Biochemical Blood Parameters, and Survival of Perch Perca fluviatilis Juveniles

摘要

The results of an evaluation of the effect of experimentally dosed salinization and salinization with a simultaneous moderate increase in temperature on somatic indices, biochemical blood parameters, and the survival of perch Perca fluviatilis fingerlings are presented. The limit of salinity tolerance for perch fingerlings used in the experiment turns out to be a mineralization value of 8 g/L. An increase in temperature leads to a decrease in the tolerance limit of perch fingerlings during salinization to 5.3 g/L. Under conditions of elevated temperature and mineralization, maximum mortality is noted, as well as the lowest values of the condition factor and the hepatosomatic index of fish, indicating the debilitation of experimental individuals, which is determined by the revealed disorders of water homeostasis. An increase in energy costs with an increase in temperature is consistent with the data of an increase in the load on the excretory system of fish due to an increase in the permeability of fish tissues, which leads to a decrease in the content of basic inorganic ions in blood plasma. At the background temperature, chronic exposure to increased mineralization also leads to the depletion of the metabolic reserves of the fish body and the predominance of catabolic processes, which is confirmed by the low content of total protein and protein metabolism metabolites in blood plasma.