Influence of interspecific hybridization on fitness-related traits in Siberian sturgeon and Russian sturgeon

Polyploidy in sturgeons makes them highly susceptible to interspecific hybridization, and these interspecific hybrids have been described in nature as well as in captivity. Nevertheless, the fitness-related traits between sturgeon hybrids and pure species have been poorly compared as yet. In the present study, we compared the reproductive parameters such as fertilization rate and hatching rate, growth traits and genetic polymorphism in the artificially produced hybrids of the Siberian sturgeon (Acipenser baerii) and Russian sturgeon (A. gueldenstaedtii) with their purebreds. Fertilization and hatching rates were found to be significantly higher in Siberian sturgeon (♀) × Russian sturgeon (♂) hybrid group compared to purebreds. The highest cumulative survival rate was determined in purebred groups until 151 days post-hatch (dph); however, this trend changed and Russian sturgeon purebred showed the lowest cumulative survival rate (0.21%) by 913 dph. Similarly, the lowest average body weight was recorded in Russian sturgeon purebred group (264 g). In contrast, the highest average body weight was recorded in Russian sturgeon (♀) × Siberian sturgeon (♂) hybrids (435.3 g) and the highest cumulative survival rate was recorded in Siberian sturgeon (♀) × Russian sturgeon (♂) hybrids (12.32%) by 913 dph. No significant differences were found at heterozygosity levels among studied crosses. Our results showed that studied sturgeon hybrids had higher survival and growth if compared with the purebreds under provided hatchery conditions.