Stock assessment and management implications of golden grey mullet (Liza aurata Risso, 1810) in Iranian waters of the Caspian Sea

Recent changes in the Caspian ecosystem have caused changes in the absolute and relative abundance of the commercially important golden grey mullet (Liza aurata) in Iranian waters. In order to adjust for these changes a more rigorous management of this fishery resource is required. The present study examines the biomass of golden grey mullet during 19912010. Estimates of fMSY, yield-per-recruit and spawning biomass-per-recruit are presented for various harvesting strategies of Fmax, F0.1, F35%, and a method is proposed for estimating acceptable biological catch (ABC) that accounts for large differences in the quality and quantity of information and available data. Biomass estimates of golden grey mullet, derived from a biomass-based cohort analysis, increased from 13527 tonnes in 19911992 to 20100t in 20002001, and declined to the lowest level (11000t) in 20072008. In 20092010, the total biomass was estimated to be 14400t. The ABC was estimated at 2200t in 2010. Golden grey mullet is vulnerable to environmental factors, which should be considered in the stock assessment and management of the fish.