Morphological analysis of resorption and degenerative processes in gonads of fishes — representatives of different families in reservoirs Dagestan part of the Middle Caspian Sea

Abstract

In recent decades, the vulnerability of the Caspian Sea ecosystem has been observed due to large-scale anthropogenic impact. Due to the limited number of studies on resorption and degenerative processes in fish gonads, it was important to evaluate these regularities in commercial fish species — representatives of different families in the water bodies of the Dagestan part of the Middle Caspian Sea. In the process of our own research and analyzed literature data, the peculiarities and character of resorption passage when it is of mass character were revealed and the reasons causing it were established. In addition, the phases (stages) and conditions necessary for this process, its duration and irreversibility were studied. The biological significance of resorption has been established. Disturbances revealed in the external morphology of germ cells may be a predictor of profound changes in their structure and function. To clarify and elucidate the possibility of participation of individuals of the analyzed fish species in the spawning process with abnormal types of gonads, it is necessary to conduct a more detailed study of the sex glands at different levels of their organization, including cellular, tissue and organ levels. All the obtained factual data, regularities and revealed peculiarities in the reproductive processes in the studied species with different biology provide an opportunity for further scientific knowledge of all parts of the reproductive cycle in fish in different ecological conditions. We consider the revealed peculiarities of functioning of reproductive systems, mechanisms of adaptation of fishes to different conditions of existence as significant and necessary for solving many theoretical questions — in the field of morphofunctional and ecological analyses of evolutionary process, as well as such urgent practical problems as obtaining artificially full-fledged eggs and milk for fish breeding in pond conditions; for biologically justified exploitation of fish resources in natural reservoirs, which provide fish with high fecundity.