Population dynamics of sturgeon in the southern part of the Caspian Sea

• Main Author: Tagavimotlagh, S. A.
• Published: Swansea University 1996
• Subjects: 636
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639150

Five years' data of the Beluga, <I>Huso huso, </I>Stellate Sturgeon, <I>Acipenser stellatus</I>, Persian Sturgeon, <I>A. persicus</I> and Russian Sturgeon, <I>A. guldenstadti</I>, in the southern Caspian Sea were analysed for sex and age, and length and weight composition. The von Bertalanffy growth parameters, and total, natural and fishing mortalities were estimated. Yield-per-recruit curves were derived from each species, based on growth parameters and mortality rates, and the optimum fishing mortality in terms of yield-per-recruit was calculated as a basis for sturgeon fishery management in the Caspian Sea. Age of the sturgeons was determined from the fin ray sections. In all five years, for all the species, there were more females than males in the catches. Catches of fish older than 20 years were a very low percentage. Von Bertalanffy growth parameters for each species were estimated for sexes separately. For female Beluga, the values of L<SUB>∞</SUB> and K were estimated for three growth stanzas as 320 cm and 0.065 for juveniles, 450 cm and 0.029 for the middle stanza and 533 cm and 0.023 for older fish. For male Beluga and other species the values of L<SUB>∞</SUB> and K were estimated both from L<SUB>max</SUB> and by using the Fishery Science Application System (FSAS) computer program. L<SUB>∞</SUB> and K for male Beluga were estimated as 270 cm and 0.086 using L<SUB>max</SUB>, 302 cm and 0.072 using FSAS. For female Stellate Sturgeon L<SUB>∞</SUB> and K were 213 cm and 0.062 using L<SUB>max</SUB>, 188 cm and 0.104 using FSAS; and for males 190 cm and 0.083 from L<SUB>max</SUB>, 171 cm and 0.113 by FSAS.