Research of fish breeding, biological and hematological parameters of paddlefish Polyodon spathula (Walbaum, 1792) females, matured in pond conditions in Astrakhan region

Abstract

The fish-breeding, biological and hematological parameters of paddlefish females matured in the pond conditions of the scientific and experimental aquaculture complex “BIOS” were investigated. The studies were carried out during the period of obtaining mature oocytes for fish breeding purposes. The reproductive function of female paddlefish was judged by the following parameters: body weight and timing of reaching sexual maturity, spawning intervals, egg yield, absolute and relative fecundity, percentage of fertilization and embryo development, and prelarvae yield. The physiological state of females was assessed according to the following parameters: white blood cell (WBC) count, hemoglobin concentration (Hb), total serum protein (TSP). The results obtained were compared with published data on female paddlefish in natural habitat and on females acclimatized in another region. Materials were obtained on paddlefish females, once and repeatedly ripened in the pond conditions of the Astrakhan region. Some data were obtained for the first time, but not in sufficient volume to draw generalizing conclusions. The investigated broodstock of the paddlefish NECA “BIOS” is very heterogeneous, there are females that reached sexual maturity at the age of 9–14 years, but some individuals matured at 20–23 years old, which is very late for paddlefish. The eggs yield was low and averaged 12.2% of the body weight of females, while in natural conditions it reaches 20% and more. It was not possible to carry out a comparative analysis of the obtained results of hematological studies, since there are very few published data on the physiological state of paddlefish breeders both in natural conditions and acclimatized in the European territory. The results obtained can be used in work with paddlefish producers in artificial conditions, as well as a basis for further studies of paddlefish hematological parameters in aquaculture.