Population structure and growth aspects of blue swimming crab, Portunus pelagicus, in Bardawil Wetland, Egypt | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 52, Volume 26, Issue 4, July and August 2022, Pages 885-903 PDF (891.1 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejabf.2022.255480 | ||
| Author | ||
| Tamer A. El-Betar et al. | ||
| Abstract | ||
| Based on the growth and population variables, the present study was achieved to evaluate the current status of Portunus pelagicus in Bardawil Wetland, Egypt, providing a basis for sustainable development in the fishery sector. About 4065 specimens of Portunus pelagicus were collected from the catch of trammel net, with a carapace width of 4.2 to 15.6 cm, most of which were medium-sized. The carapace width-weight relationship clarified a positive allometric growth pattern. The overall mean value of the condition factor (5.3) revealed a good condition and suitable habitat. The estimated sex ratio was 1:1.05 for males and females, respectively, which varied insignificantly from the expected ratio of 1:1 (X2, P > 0.05). Three age groups (0+, 1+ and 2+ year) were estimated in which each age group individuals constituted about 11.7, 82.7 and 5.5% of the population, respectively. Von Bertalanffy growth parameters were CW∞ = 16.6cm, K = 1.4 y-1, and t0 = - 0.918. The 1st capture (CWc) was detected with a carapace width of 7.80 cm. 4.68 y-1, 2.25 y-1 and 2.43 y-1 were the estimated values of total (Z), natural (M) and fishing mortality, respectively. The highest value of fishing mortality compared to the biological reference points; Fopt= 1.125 and Flimit= 1.50 y-1; indicates overexploitation, which was confirmed by the exploitation rate of 0.57. The predominance of Portunus pelagicus may refer to the leak presence of natural predators, which are heavily exploited. Restoring the biological balance is an urgently required step. | ||
| Keywords | ||
| Blue swimming crab; Population structure; Growth aspects; Bardawil Lake | ||
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