Stock assessment of bonyfishes in the Iranian coastal water of the Caspian Sea (2004-2005)

For gathering of data on biometry and catch statistics, 5 mobile working group in the regions of Anzali, Kiashahr , Noshahr , Babolsar and Torkmen were involved from the start (2004.10.23) to the end of fishing season (2005.04.10). Gathered data were entered to the computer based on species. For data analysis different methods were undertaken such as Bertallanfy equation for growth parameter Beverton and Holt for total mortality rates, pauly's imperical model for natural mortality rate and cohort Analysis for biomass estimation. Total catch with taking into account of poaching, was estimated 15140 tons reported by scientific committee of catch and fishing harbor relief of Iranian Fishery Company. The total recorded catch of beach seine cooperatives was 10644 tons that comprise 70.2% of the total catch. Total catch of Caspian Kutum was estimated 6612 tons that had 1856 tons (22%) decrease with comparison of the last year. Biomass of Caspian kutum in Iranian coastal Water of the Caspian Sea in 2003-2004 estimated about 20400 tons. The total catch of golden gray mullet was estimated 4425.6 tons that constitute 29.2% of total catch of bony fishes. Biomass of this species was estimated 12200 tons and based on this amount of biomass, Maximum Sustainable Yield (MSY) was calculated as 3577 tons. Long nose mullet comprised only 1.4% of the mullet catch. The catch of common carp in 2004-2005 fishing season continued its increasing trend and caught in amount of 3087 tons by beach seine cooperatives that had 2.2 fold increase in comparison of previous fishing season. Most of the catch occurred in Golestan province and was immature and undersize and the length frequency modes showed moving towards bigger size and older age groups in comparison of previous fishing season. The catch of pick perch in 2003-2004 decreased with comparison of the last year and estimated about 22.5 tons. Most of the catch of pick perch was immature and undersize. Approximately all of the catch is due to releasing of fingerling of this species by Fishery Company especially in Guilan province. Total catch of bream was estimated 27.4 tons and most of which was immature and undersize. Population of asp is critically endangered and the catch of this species is very low (500 kg). Restocking of this species must be considered by Iranian fishing company