Age, growth and mortality of saddled bream, Oblada melanura (linnaeus, 1758) in Abu Qir Bay, Egypt.

Age, growth and mortality of saddled bream, Oblada melanura
(linnaeus, 1758) in Abu Qir Bay, Egypt.
Hatem H. Mahmoud
National Institute of Oceanography and Fisheries, Alexandria, Egypt.
E mail: [email protected]
Received 19th January 2010, Accepted 2nd February 2009
Abstract
Age, growth, mortality rates and exploitation ratio for Oblada melanura in Abu Qir Bay (Egypt) were
determined. The examined sample ranged between 12 and 29.2 cm total length and from 25.6 to 352 gm total
weight. The length – weight relationship was found to be expressed by the equation W= 0.017 L2.9342. Age was
determined by using body scales readings. Length – scale relationship for sexes combined was represented by the
linear equation L = 1.0624 S + 1.286. Growth in length and in weight were determined. Von Bertalanffy growth
parameters were estimated (L∞= 33.833 cm, k= 0.242 year-1
, to= -0.669 year-1 & W∞ = 522 gm). The maximum age
(tmax) was 12.4 year and the growth performance for length (øL) was 2.442. The coefficients of total mortality (Z),
natural mortality (M) and fishing mortality (F) were 0.958, 0.563 and 0.349 year
-1 respectively. Survival rate (S) was
0.38. Length and age at first capture were 15.68 cm and 1.90 year respectively. Length and age at recruitment were
13.95 cm and 1.53 year respectively. The estimated exploitation ratio (0.412) indicates that, this species in Abu Qir
Bay is not overexploited.
Keywords: Abu Qir Bay, Age, Growth, Mortality, Sparidae, Oblada melanura.