Some data on the reproductive system condition of Antarctic toothfish (Dissostichusmawsoni) males and females from the Indian Ocean area in the summer period

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The study deals with reproductive characteristics of the life history of Antarctic toothfish caught in the seamounts of the Indian Ocean area of the Antarctica in the fishing period 2004- 2005. This fish species is one of the important deepwater resources of Antarctica. The study is a part of complex investigation of the life history adaptations of this fish species in the different areas of the Antarctica. The morphological parameters, indices of gonads have been described. The histological criteria of the assessment of the ovary maturity stages and cytological parameters of oocytes and type of the toothfish oogenesis have been determined. Under the maturing of toothfish ovaries from the stages II to IV show a slow increase in oocyte diameter. It was shown that for Antarctic toothfish during the fishing period the individuals with gonads of the III late stage of maturity were dominated. Their ovaries contained three size groups of oocytes: cytoplasmic group and two groups of vitellogenous oocytes. Antarctic toothfish was not matured for spawning in the Indian Ocean area of the Antarctica in the investigation period.