Age, growth, mortality rates and corresponding yield estimates of the snubnose emperor Lethrinus borbonicus from south Sinai coast, Gulf of Suez, Egypt

Age-based demographic analysis were conducted to assess the current status of fished stock of the snubnose emperor Lethrinus borbonicus in South Sinai coast, Gulf of Suez, Red Sea. L. borbonicus is one of the most abundant emperors in the area, representing about 10% of the total artisanal fishery in south Sinai coast. Seasonal samples were collected from the commercial small scale fishery during the period from June 2005 until April 2007. The otoliths were used for age determination. Validation of the ageing method was carried out by analyzing the seasonal length frequency distributions. The life span was found to be four years. The estimated von Bertalanffy growth parameters from otolith age reading were L_∞= 36.76 cm, K= 0.344 year^-1 and to= -0.321. Instantaneous rates of fishing mortality (F) were beyond the limit reference point compared with estimated instantaneous rates of natural mortality (M), indicating that there is currently a risk to the sustainability of that stock. Results of the exploitation rate (E=0.583) and relative yield per recruit showed that the snubnose resource in the Gulf of Suez is overexploited and that small 16 individualsare the target of the fishery referring to recruitment overfishing also. Some implications for the fishery management for decreasing fishing effort are required.