The state of sex glands and the size-age composition of the male Caspian Sea stellate sturgeon Acipenser stellatus Pallas during the marine period of life
Voprosy Ichtiologii 20(6): 833-843
ISSN/ISBN: 0042-8752 Accession: 006406873
The condition of gonads in different seasons in all of the distribution area, the periods of onset of some spermatogenesis phases and size-age composition were studied in 981 male A. stellatus Pallas individuals, caught in the Caspian Sea in 1974-1978. The data were subjected to variation statistical treatment. A histological examination of testicles was performed. Most male individuals reached sexual maturity at an age of 10-12 yr, with a 110-115 cm body length. The process of sex gland maturation was most active in the summer and autumn. This process slowed down in the winter. The average length, weight and age indices of male individuals that foraged in the northern, central and southern parts of the Caspian Sea were similar. Recruitment numbers decreased in the northern part of the Caspian Sea due to a decrease in river run-off. The proportion of large fish increased. A. stellatus males were represented by generations that appeared after the flow of the principal rivers in the basin was brought under control. Males of 1964-1971 generations do provide and will continue to provide commercial fishing for at least the next 5 yr.