Stock status assessment of sharpnose mullet (Liza saliens) by using overfishing indicators in southern part of the Caspian Sea (1991-2011)

The main objective of the present study was assessment of stock status of sharpnose mullet by using indicators of overfishing, condition factor and relative weight in Iranian waters of the Caspian Sea during 1991-2011. Three fisheries indicators in catch were: 1. percentage of mature fish, with 100% as target; 2. percent of specimens with optimum length, with 100% as target; and 3. percentage of mega-spawners, with 0% as target. Over this period, the condition factor and relative weight had a decreasing trend. The range of length with optimum yield was between 28 and 34 cm. The mega-spawner measured as fish a size larger than 34 cm. According to these three indicators, the percentage of mature (fork length>28 cm), optimum size and mega-spawners were 8.9-72.4%, 8.8-50.4% and 0%-23.9%, and 39.5%±16.1, 30.7%±11.8 and 9.2%±7.7, respectively in average (±S.D). This length structure is a matter of concern. Therefore, for reservation and rebuilt of sharpnose mullet in the Caspian Sea, the target would be to all (100%) fish spawn at least once, using bigger mesh size in cod end (e.g. 33 mm, during whole fishing season), also, the aim would be to implement a fishing strategy that result no (0%) mega-spawners being caught, and the main catch focus on optimum length.