ADVANCES IN FISH SPERM CRYOPRESERVATION: TAXONOMICAL CONSIDERATION

Current thesis is devoted to exploration of the current state of fish sperm cryopreservation in relation to aquaculture and conservation measures with special focus on fish sperm taxonomy. Based on intensive analysis of available literature on the topic it was found that nowadays cryopreservation is considered as one of the important components of effective strategy to save endangered species and also as an unique tool that can be used in the aquaculture industry to facilitate broodstock management. It was summarized that nowadays sperm from 233 actinopterygian fishes belonging to 22 orders was cryopreserved applying different cryopreservation protocols with varying success. These data are presented in the form of a table in supplements. To create this database the scientific citation indexing service Web of Science (Clarivate Analytics) was used as the basic source of information subsequently supplemented by library sources. From the data obtained it is assumed, that the main part of studies was focused on economically important fishes and the minor part of the studies was focused on endangered fish species. Of special interest is the observation that similar cryopreservation method may be applied with greater success in fish species belonging to taxonomically-related groups. Fish taxonomical diversity is associated with specific morphological and physiological features of their gametes. That in turn entails the necessity to develop species-specific protocols of sperm cryopreservation for species not studied yet and being under risk of extinction. Taxonomical analysis shows that the highest number of fish species, the sperm of which was cryopreserved, belong to the order Perciformes, followed by Cypriniformes, then Siluriformes, Characiformes, Salmoniformes and Cyprinodontiformes. It is noted that these orders represent about 33% of extant fish orders and it is obvious now that more attention should be payed to develop protocols for representatives of orders non-involved into cryobiological studies. This bachelor's work provides the most modern review of fish species in which sperm was cryopreserved and these data may serve as a base and bibliographic source for further research in fish sperm cryobiology