Primary and secondary responses of Siberian sturgeon (Brandt, 1869) Acipenser baerii to handling stress in two different sizes

The aim of this study was to investigate the primary and secondary responses of Siberian sturgeon (Acipenser baerii) to handling stress on at two different sizes. In this study, the fish were distributed in small and large sizes with mean weights of 672.27 ± 2.54 g and 1078.5 ± 5.30 g, respectively, in six replicates with equal biomasses. Six blood samples were randomly taken before the stress thereafter three blood samples were taken at 1, 3, 6, 12 and 24 hours after acute stress (the fish were exposed to air for two minutes) to examine the physiological changes of blood. Cortisol levels increased in both sizes, although there was no significant difference in experimental treatments. According to the results, blood glucose increased in large size after stress and a significant difference was observed (p 0.05), but no significant was observed in small size (p 0.05). Lactate levels significantly increased in both sizes after stress (p 0.05). The results showed that large-sized fish show larger stress response than small size, and therefore they tend to be more susceptible to stress.