Assessment of three nemipterid stocks based on trawl surveys in the Gulf of Suez, Red Sea

Abstract

The population structure of three Nemipterid species (Nemipterus japonicus, Nemipterus bipunctatus and Nemipterus zysron) from the Gulf of Suez was investigated. A total of 3663 specimens (2597 N. japonicus, 576 N. bipunctatus and 490 N. zysron) were collected during the fishing season 2014/2015 in the Gulf of Suez. The maximum life span estimated from otolith reading was 5 years for N. japonicus and N. bipunctatus while, it was 4 years for N. zysron. The parameters of von Bertalanffy growth equation were L∞ = 31.66 cm, K = 0.24 year−1 and to = −1.2 year for N. japonicus; L∞ = 29.55 cm, K = 0.26 year−1 and to = −1.2 year for N. bipunctatus and were L∞ = 24.69 cm, K = 0.38 year−1 and to = −0.84 year for N. zysron. The estimated exploitation rate for the three species exceeded the optimum exploitation rate, indicating an overexploitation of the nemipterid species in the Gulf of Suez. The yield per recruit analysis revealed that the fishing pressure of the trawling fleet in the Gulf of Suez, has overridden the critical level. Findings suggest that decrease in the fishing effort of trawl fishery and increase the length of the mesh size is required for the protection of the nemipteridae resources in the Gulf. Keywords: Trawl, Age and growth, Nemipterid species, Exploitation rate, Yield per recruit