Population dynamic and fisheries management of Eeuropen sea bass,Dicentrarchus labrax (f. Moronidae) from Bardawil lagoon, North Sinai, Egypt | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 4, Volume 15, Issue 1, January 2011, Pages 43-56 PDF (249.7 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.2011.2077 | ||
| Author | ||
| Mohamed Ahmed | ||
| Faculty of Environmental Agricultural Sciences, Suez Canal University, Egypt. | ||
| Abstract | ||
| Population dynamic of European seabass, Dicentrarchus labrax was studied from a small scale fishery of Bardawil lagoon. 1688 specimens ranged between 18.2 and 64.7 cm TL and 62 to 2823 g total weight, were collected from August, 2009 to November, 2010. The relationship between length and weight was estimated as W = 0.014 L2.883. Age was determined using scales’ reading technique for 586 individuals and the longevity of this species was found to be 6 years. Growth in length and weight at the end of each year was calculated. The growth parameters of the von Bertalanffy equation were calculated as L∞ = 70.82 cm, K = 0.35 yr-1 and t0 = -0.217 yr. The observed and predicted extreme lengths were 64.5 and 70.05 cm, respectively. Total, natural and fishing mortality rates were 1.03 yr−1, 0.39 yr−1 and 0.64 yr−1, respectively. The current exploitation rate (E = 0.6229) indicated that the stock of seabass in Bardawil lagoon is heavily exploited. The length at first capture Lc was estimated as 20.16 cm. The maximum allowable limit of exploitation (Emax) was 0.5, while that at maximum economic yield was 0.42. Based on these results, this important species may be in danger of severe declines in the near future where the stock was over-fished and small fish were unprotected by the current size regulation. Also, the results indicated that an increase of Lc would be associated with an increase in yields at the existing exploitation rate. Thus, for management purpose, the current exploitation rate must be reduced from 0.62 to 0.31 (50%) or the present length at first capture (Lc) should be increased from 20.16 to 32 cm at the current the exploitation rate. | ||
| Keywords | ||
| Population Biology; Fisheries regulation; Dicentrarchus labrax; Bardawil Lagoon; Egypt | ||
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