BIOLOGICAL CHARACTERISTIC OF THE REPRODUCTIVE GUILD OF ACIPENSER RUTHENUS (LINNAEUS, 1758) IN THE SEVERNAYA DVINA RIVER

According to results of ichthyological monitoring the sterlet population in middle part Severnaya Dvina river spring period 2018–2020 established a greater dependence value catches stationary traps on dynamics water level river, compared with temperature. On spawn places located traps, dominates both quantity and mass. Average catch per unit fishing effort (CPUE) is more dependent than Age length composition represented by two-thirds fish younger age classes (3–5+) small sizes (30–45 cm 0.2–0.6 kg). The sexual structure spawning about 80% males. currently grow faster 70 years ago – probably due an increase average temperature river. In pre-spawning parts proportion maturing sexually mature females males 90%. number past-spawners increases increasing Currently, grows slowly 50–60s 20th century. Sterlet intensively fed during period. basis nutrition chironomids caddis fly larvae. Secondary objects are bivalve mollusks blackfly. Random characterizing nutritional spectrum include larvae flies, butterflies, hemipterous eggs. There no significant differences its size