Siberian sturgeon Acipenser baerii (Brandt, 1869) (Acipenseridae) of the Yenisei river. Part 1. Herd structure (overview)

Abstract

Siberian sturgeon is widely distributed in the river basin. Yenisei. Its range, the structure of the herd, including residential and semi-anadromous forms, and the scheme of migrations are described. The concept of population continuums is analyzed. Sturgeon is one of the largest fish on the river. Yenisei, reaches 124 kg of mass. It is shown that over 100 years of research, the linear and weight growth of the Yenisei sturgeon remains at the same level. Late sexual maturation of this species has been recorded: males become sexually mature at the age of 17–19 years, females mature at the age of 20–24 years. The intervals between successive spawnings in females are 5–6 years, males — 3–4. Absolute individual fecundity ranges from 50 to 750 thousand eggs. By the nature of the diet of sturgeon in the basin of the river. The Yenisei is a benthophage that consumes the larvae of chironomids, caddisflies, stoneflies, mayflies, midges, amphipods, and oligochaetes. Age and sex differences in nutrition are not observed. Information about the organization of sturgeon fishing on the river is given. Yenisei since the middle of the 19th century. The main share of the prey of this species fell on the lower reaches of the river; the catch of the spawning part of the population during the spawning migration brought about 10% of the total prey. It is noted that large-scale anthropogenic impacts have significantly changed the habitat of this species. The number and stocks of the Siberian sturgeon in the basin of the river. The Yenisei was noticeably reduced by the beginning of the 21st century.