Comparative evaluation of sturgeon larvae and juveniles reared under control of seasonal propogation of the wild and domestic breeders

Abstract

Sturgeon populations (Acipenser gueldenstaedtii and A. stellatus) in the Sea of Azov basin are maintained largely through stock enhancement. A monitoring is in operation for biological characteristics of juveniles, including body length and mass, physiological‐biochemical indices, teratology, thermal stability, salt resistance, oxygen deficiency resistance and melanophore adaptive response as indicators of physiological fitness, and neuro‐pharmacological testing with a sedative (MS‐222). Behavioural experiments include the assessment of background movement and reactivity to the effect of low/high frequency sounds and light of long/short duration. Juveniles obtained from breeders in which the reproductive cycle had been delayed for up to 90 days did not show significantly different levels of morphological anomalies compared to juveniles obtained with conventional reproductive techniques. The most frequent defects are observed in pectoral fins (up to 20 per cent) and olfactory organs (up to 10 per cent). Fingerlings showed and adequate and timely adaptive reaction of melanophores towards dark and light background. The experiment demonstrated that sturgeon fingerlings produced under controlled conditions are euryhaline and robust to thermal and oxygen stress. Some differences in biological attributes were noted between juveniles obtained from wild and domesticated breeders of A. gueldenstaedtii and A. stellatus.