Use of Length–Frequency Analysis for Stock Status, Growth and Mortality Estimation of the Striped Eel Catfish Plotosus lineatus (Thunberg 1787) from Gulf of Aqaba, Egypt

The present study aimed to determine the age composition, growth parameters, natural and fishing mortality coefficients and level of exploitation of the striped eel catfish (Plotosus lineatus) from the Gulf of Aqaba, Egypt. To assess the population status, the length frequency data were analyzed using the FiSAT computer program. The parameters of the von Bertalanffy growth curve were TL∞ = 31.36, 29.29 and 32.52  cm for males, females and sexes combined respectively, while the obtained K values were 0.41, 0.50 and 0.45 y^-1 for males, females and sexes combined respectively. The instantaneous mortality coefficients of the whole population were estimated as follows: total mortality (Z) = 1.26 y^-1; natural mortality (M) = 0.74 y^-1, and fishing mortality (F) = 0.52. The stock showed a growth performance (ø) value of 2.68. The current exploitation rate of the species was calculated as 0.41. The analysis of relative yield per recruitment and relative biomass per recruitment showed that the maximum allowable exploitation rate at maximum sustainable yield (MSY) for the striped eel catfish fishery in the Gulf of Aqaba is 1.0 which is more than the currently observed exploitation rate. The results suggest that the striped eel catfish stock in the Gulf of Aqaba is not overfished and is within safe exploitation limits. It is recommended that a regular monitoring program for the stock should be in place, and any proposal for a change in exploitation rate should be assessed according to the stock status at that point of time.