BIOLOGICAL ASPECTS OF THE EUROPEAN SEA BASS (DICENTRARCHUS LABRAX L., 1758) FROM BARDAWIL LAGOON, NORTH SINAI, EGYPT

Abstract

The present study investigated the biological aspects of the European sea bass (Dicentrarchus labrax) from Bardawil Lagoon, North Sinai, Egypt. Monthly random samples of D. labrax were collected from the commercial catch of different landing sites of lagoon during two fishing seasons from May 2015 to December 2016. The length-weight relationship, condition factor, age composition, and fish growth were studied in the current study. The exponent ‘‘b” of the length-weight relationship resulted in isometric mode of growth, since the value of b = 3.0067 in the power equation: Weight = 0.0093 × length3.0067. The mean highest values of condition factor (K) of D. labrax were recorded in November (where K = 1.26). Growth parameters such as the asymptotic length (L∞); growth rate (k); the hypothetical age at which fish would have zero length (t0), and the asymptotic body weight (W∞) were estimated as 75.31 cm, 0.1221 year−1, −1.8703 year and 4088.99 g, respectively. Total mortality (Z), natural mortality (M), and fishing mortality (F) were 0.8786, 0.3153, and 0.5633 year−1,respectively. Exploitation rate (E) was 0.64, which indicated that the stock of the sea bass in the research area is heavily exploited. However, degree of well-being of D. labrax in the lagoon was detected. Overall, the present study concluded that it is essential to maximize the length at the first capture to be larger than that at the first sexual maturity (> 30.0 cm) by widening the mesh size used to catch D. labrax to protect this species from extra-exploitation.