Stock assessment of the alien species Brushtooth lizard fish, Saurida undosquamis (Richardson, 1848) in the Egyptian Mediterranean coast

Abstract

The exploitation status of Saurida undosquamis (Richardson, 1848) from the Egyptian Mediterranean coast was assessed. Fish samples (3444 specimens) that ranged between 9 and 36cm total length were collected from commercial trawlers. The information used for the assessment of the stock consisted of catch length structure, length–weight relationship and Von Bertalanffy’s growth parameters. The vector of natural mortality (M) by age was calculated using the PROBIOM Excel spreadsheet while total (Z) and fishing (F) mortalities, length cohort analysis and Beverton and Holt Yield per recruit analysis were performed by FiSAT, LFDA and Vit 4 win programs in order to estimate the limit and target reference points of stock exploitation.The results revealed that the average fishing level of S. undosquamis (0.575) was higher than the biological reference points F0.1 (0.247) and Fmax (0.368). Moreover the ratio between Fc and F0.1 was 2.326 indicating that, the S. undosquamis stock in the Egyptian Mediterranean coast is in a state of high overfishing and severe overexploitation.