Relative abundance of kutum (Rutilus kutum) in beach seines of the Caspian Sea

The kutum (Rutilus kutum) is one of the most important and commercial species of the bony fishes and comprises up to 70% of catch composition in Iranian waters of the Caspian Sea. Catch and effort data of the beach seine fishing cooperatives as well as the distribution and important species index (ISI) in the fishing areas were assessed between 1996 and 2011. The kutum had a wide distribution in the Iranian waters of the Caspian Sea during the study period. The minimum proportion in catch, distribution and ISI for kutum were observed in the east coast of the Golestan province, while the maximum values were observed in the Guilan province (before 2006) and Babolsar fishing area (from 2007 to 2011). The ISI was higher between 2006 and 2011 than the previous years, and the maximum level of this index was obtained 78 in 2008. The CPUE increased from 1996 to 2011. The maximum CPUE between 1996 and 1999 was in the range of 220.3 to 384.5 kg/haul (observed in Astara fishing area), while between 2008 and 2011 the maximum CPUE was in the range of 364.3 to 566.3 kg/haul (observed in Babolsar fishing area). In general, distribution and ISI of kutum between 1996 and 2011 were higher in the Mazandaran province than the other fishing areas.