Growth parameters and mortality rates of Gerres oyena, Forsskål, 1775 (Common silver-biddy) form Hara Biospher Reserve, Iran

Population parameters of Common silver-biddy (Gerres oyena) were studied in Hara Biospher Reserve from September 2016 to August 2017. All fishes were sampled by boat trawl, beach seine and trapping barriers. Growth parameters were determined using the monthly length–frequency data. The Mean total length was calculated 8.5±1/35 cm for Common silver-biddy. The value of L∞ and K were calculated 18 cm and 1.5 yr-1 respectively. The rate of natural mortality (M) were estimated 2.68 yr-1. The length-weight relationship were determined as W= 0.0088 L 3.21 and W= 0.00887L 3.21 for Common silver-biddy. Results showed these fishes were juvenile and emphasized on supporting roles of creeks for Gerridae as nursery ground.