Morphological characters of artificially induced hybrids of Siberian sturgeon, Acipenser baerii baerii Brandt, and green sturgeon, Acipenser medirostris Ayres

The morphometric characters of artificially induced hybrids of Siberian sturgeon, Acipenser baerii baerii Brandt, with green sturgeon, Acipenser medirostris Ayres, were examined until the fish achieved sexual maturity. The measurements encompassed 29 measurable and six meristic characters. Throughout the studied period of fish development, the greatest changes were noted in body depth (H) and head depth (HC). The characters that changed the least with respect to fish length were fork and body (l₁, l₂) lengths; the predorsal and preanal (aD, aA) lengths; and also some of the characters associated with head size - the width of the space in the lower lip (il) and the length of the barbels (lc). Until the age of 4+, the head shape changed with regard to its length, width, and the proportions of the front and back sections. It was confirmed that the fish from intensive culture in the recirculating systems exhibited greater similarity in morphometric characters to adults than did the fish from pond culture. Evidence of this was noted primarily in the characters that were the most typical of adult individuals, such as the relatively shorter head and rostrum.