Fishery Biology and Population Structure of the Blue Swimmer Crab, Portunus pelagicus, from the Red Sea, Egypt

Bibliographic Information
Authors: El-Kasheif M.A.; El-Far A.M.; El-Kasheif A.M.; Ibrahim S.A.; Flefel H.E.
Journal: Egyptian Journal of Aquatic Biology and Fisheries
Publisher: Egyptian Society for the Development of Fisheries and Human Health
Publication Date: 1 December 2021
Volume / Issue: Volume 25 / Issue 6
Pages: 269–283
Article No.: 20
ISSN: 11106131
DOI: 10.21608/EJABF.2021.211506
Scopus: View on Scopus
Document Type: Article
Access: All Open Access; Gold Open Access
Authors and Affiliations
El-Kasheif M.A., National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt; El-Far A.M., National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt; El-Kasheif A.M., National Food Safety Authority( NFSA), Cairo, Egypt; Ibrahim S.A., Faculty of Science, Benha University, Egypt; Flefel H.E., Theodor Bilharz Research Institute ( TBRI ), Giza, Cairo, Egypt
Abstract
More than 300 MT of blue swimmer crabs (BSC), Portunus pelagicus, are annually captured from the fisheries of the Egyptian Red Sea waters. During the last 20 years, a decline has been witnessed in the production of this species. For management purposes, information about the fishery's biology and population structure is required. Hence, monthly samples of P. pelagicus were collected from the commercial catch of Hurghada landing site, Red Sea, Egypt during the period from November 2017 to October 2018. A number of 1190 specimens were measured for morphometric relationships, sex ratio, age determination using carapace width frequency, population structure, mortality rate and exploitation ratio. The study revealed that P. plagicus was targeted by trammel nets and caught by a small bottom trawler as a by-catch. Carapace width-total weight relationship showed positive allometric growth (b-value= 3.10). Higher condition factors were observed in the small individuals. Four age groups were determined and age group +I was dominant by number (60.6%). Parameters of the von Bertalanffy equation were 21.19 cm, 0.414 year-1, and-0.998 year for CW∞, K and to, respectively. The carapace width at first capture was estimated (CW50 = 8.7 mm). The mortality rates were calculated as 2.929, 1.285 and 1.644 year-1 for total, natural and fishing mortalities, respectively. The blue swimmer crab fisheries on the Red Sea is over-exploited (E= 0.65) by the trammel net. Some management measures were suggested to maintain its stock for sustainability. © 2021, Egyptian Society for the Development of Fisheries and Human Health. All rights reserved.
Keywords
Fishery biology; Population structure; Protunus plagicus; Red Sea
Citation Information
Scopus Citations: 12
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