Fish-breeding and biological characteristics of pure species and hybrids of Siberian sturgeon and Russian sturgeon in commercial breeding in an industrial fishery

The study compares commercial breeding of Siberian sturgeon, Russian sturgeon, and their hybrids in a flow-through industrial farm. The research was carried out at the Konakovo Division of the Branch for Freshwater Fisheries of the Federal State Budget Scientific Institution “Russian Federal Research Institute of Fisheries and Oceanography” (VNIIPRKH) from 2019 to 2021. Throughout the breeding period, the average water temperature was 16.3 °C, and the thermal constant was 16,195 degree days. The comparison of fish-breeding and biological characteristics of pure species and hybrids of Siberian sturgeon and Russian sturgeon under similar conditions revealed that Siberian sturgeon × Russian sturgeon (SS×RS) and Russian sturgeon × Siberian sturgeon (RS×SS) hybrids had the highest body weight, while Russian sturgeon (RS) and Siberian sturgeon (SS) had the lowest body weight. The average weight gain coefficient in experimental groups of sturgeons varied insignificantly during different breeding periods and was nearly similar at the end of breeding. The paper presents the results of nutritional value evaluation and determination of the weight ratio of individual body parts in the studied fish species. The study of gametogenesis in Siberian sturgeon and Russian sturgeon pure species and hybrids provides insight into the natural development of germ cells depending on water temperature. The onset of puberty in pure species and heir hybrids is noted at the age of three years (1024 days), and spermatogenesis takes place in cysts of males. Gonad maturity is characterized as stage IV–VI, with overmature sperm resorption. The analysis revealed similarity in germ cell development, confirming the seasonal cycle in sturgeon spermatogenesis. Female Siberian sturgeons and SS×RS hybrid have normal germ cell development, whereas Russian sturgeons and RS×SS hybrid have delayed gonad development.