An estimation of growth parameter, mortality rates and yield-per-recruit for beluga (Huso huso) living in Caspian Sea

This paper presents the results of study on age, growth, mortality rates and yield-per-recruit of Beluga (Huso huso) living in Caspian Sea. The mean length of successive years, mortality rates and yield-per-recruit studies indicated that at present the resource is under heavy fishing pressure. For the female Beluga growth was regarded as comprising of three stages, and the von Bertalanffy parameters were calculated for juveniles, for middle stanza (24 years). The value of K was the highest (0.065) for the first stanza, lower for the middle (0.029) and the lowest for the third one (0.023). Total mortality of female and male Beluga estimated from the descending limb of the catch curve using the combined data (1990-1994) were: for females, Z=0.48 per year, r=0.982, p<0.01 and for males, Z=0.38 per year, r=0.992, p