Population dynamics parameters of Bigeye grunt Brachydeuterus auratus (Pisces, Haemulidae) from the continental shelf of Côte d’Ivoire (West Africa)

[摘要] The population structure, growth, mortality, and exploitation rate of big-eye grunt Brachydeuterus auratus were examined from the continental shelf of Côte d’Ivoire (West Africa) between August 2016 and July 2018. This study provides results on fishery dynamics parameters to contribute to estimating the stock assessment of this fish species. Monthly length-frequency data were collected and analyzed using the Stock Assessment Tools-II (FISAT II) software. The total lengths ranged from 8.76 to 24.56 cm, the dominant length group ranged from 15 to 16 cm (16.9%). The length-weight relationship parameters were W = 0.00872TL3.16 (r2 = 0.94). Von Bertalanffy parameters were estimated at asymptotic total length (L∞) = 24.68 cm, coefficient of growth rate (K) = 0.46 year-1, growth performance index (Ø’) = 2.45, time at which length equals zero (t0) = -0.38 year. Mortality parameters were calculated as a total mortality rate (Z) = 1.84 year-1, the natural mortality rate (M) = 1.10 year-1, and fishing mortality rate (F) = 0.74 year-1. The exploitation rate (E) = 0.40 year-1 was lower than the optimal level, indicating that Brachydeuterus auritus fishery is not overexploited.

[关键词] Brachydeuterus auratus;Côte d’Ivoire;population dynamics;mortality;recruitment