Improving the size-selectivity of trammel net for Pomadasys stridens and Gerres oyena in Suez Bay, the Gulf of Suez, Red Sea

摘要

Size selectivity of the trammel net forPomadasys stridensandGerres oyenain Suez Bay, Gulf of Suez, Red sea, was estimated by comparing three mesh sizes 34, 37 and 40?mm for the inner layer of the trammel net. The SELECT model was used to estimate the selectivity curve. Length frequency data were fitted by five models: normal scale, gamma distribution model, normal location, lognormal distributions model, and bi-normal model. The results revealed that the best fit model of selectivity curve of the trammel nets data forGerres oyenawas obtained by the and bi-normal model, whilst the Log-normal model gave the best fit forPomadasys stridens.The length-weight relationship equations were estimated to be W?=?0.027?×?L2.735with r2?=?0.97 forPomadasys stridensand W?=?0.050?×?L2.470, r2?=?0.93 forGerres oyena.The study concluded that the mesh size of the trammel nets used in Suez Bay fishery should not be less than 40?mm especially forPomadasys stridensandGerres oyenato protect their stocks from overfishing.