Effect of body weight on morphophysiological and slaughter characteristics in Siberian sturgeon (Acipenser baerii), Russian sturgeon (Acipenser gueldenstaedtii) and their hybrid (F1 A. baerii x A. gueldenstaedtii)

The study was carried out with sturgeon fish of different genotypes cultured in a large warm-water reservoir of an industrial cage farm located in southeastern Bulgaria. The study results indicated that the influence of body weight on more than morphological and slaugter characteristics was not unidirectional in fish of different genotypes. In Russian sturgeon with increasing body weight the viscerosomatic index increased, but the relative share of head, pyloric gland, chord, bony shields significantly decreased. In the hybrid, the relative share of head without gills, fins and tail, chord decreased and the viscerosomatic and hepatosomatic indexes increased, respectively. In all studied groups, the relative share of gonads increased significantly with increasing body weight. A significant negative effect of body weight increase on some slaughter yields (Sv1 and Sv2) was found in Russian sturgeon and hybrids. In Siberian sturgeon, the higher body weight significantly increased the relative share of whole fillets in the carcass. In Siberian sturgeon and hybrids, there was no significant effect of body weight on exterior indices. Only in the Russian sturgeon the increasing body weight resulted in improved high back. With regard to fish condition, a significant influence was found only in Siberian sturgeon. The increasing body weight have a positive effect on condition index (IC) and modified Fulton’s coefficient (ICR). Keywords: aquaculture; sturgeon, slaughter analysis, fillet yield, morphometrics, condition indices