Assessment of population dynamic and fisheries management of Ethmalosa fimbriata exploited by small-scale fishery in the tropical coastal lagoon of Grand-Lahou (C?te d’Ivoire, West Africa)

摘要

This study aims to obtain informations on growth, mortality and exploitation rate of the stock of Ethmalosa fimbriata in Grand-Lahou lagoon. Samples were collected using artisanal gillnet fishery from November 2013 to October 2014. Length frequency data collected were analyzed with FISAT software using the ELEFAN package to estimate the population parameters of Ethmalosa fimbriata. A total of 2383 individuals of Ethmalosa fimbriata ranged from 5 cm to 16 cm SL (standard length) were examined. The asymptotic length (L∞) and growth rate constant (K) were estimated to be 17 cm and 0.84 year–1 respectively. Based on the growth parameters and using the catch curves procedures, the instantaneous total mortality coefficient (Z), the instantaneous natural mortality coefficient (M) and the Instantaneous fishing mortality coefficient (F) were 3.66, 1.85 and 1.81 year-1 respectively in Grand-Lahou lagoon. The exploitation rate was estimated at 0.49. Fishing mortality (F) and exploitation rate (E) were found to be below optimum levels of exploitation and indicate that Ethmalosa fimbriata is not overexploited in Grand-Lahou lagoon. The Y’/R and B’/R curves as well as all year round recruitment show that the current exploitation rate could be maintained for sustainable and rational exploitation.