BIOLOGICAL MANAGEMENT OF WHITE SEA BREAM DIPLODUS SARGUS (LINNAEUS, 1758) IN THE EASTERN MEDITERRANEAN, COAST OF NORTH SINAI, EGYPT

Abstract

The goal of the present study is to give basic information required for managing sea bream, Diplodus sargus.Samples of the studied fish (7.0-34.7 cm total length and 15.5-833.2 g total weight), were collected from January, 2016 to December, 2016from Eastern Mediterranean, coast of North Sinai. The relationship between length and weight was estimated as W = 0.0244*L2.98. Age was determined by otolith, where age groups I to V years were established. Growths in length at the end of each year were calculated as 13.44, 19.00, 23.81, 27.58 and 30.01 cm for the 1st, 2nd, 3rd, 4th and 5th year of life, respectively. The growth parameters of von Bertalanffy parameters were calculated as L∞= 40.06 cm, K = 0.2445 year-1 and t0 = -0.6711 years. Growth performance index φ′ = 2.59, as well mortality rates, were 0.7582, 0.3356 and 0.4226 yr−1 for total, natural and fishing mortality respectively. The currently exploitation rate was E = 0.56. The length and age at first capture (Lc) (Tc) were 17.7 cm and 1.7 years respectively. So, the current mesh size should be increased to maximize the length at first capture (Lc)to 22.7 cm, which achieve the highest yield per recruit at current fishing effort.