Some aspects of the biology of West African Ilisha (Ilisha africana, Bloch 1795) from the coast of Ghana, West Africa

Asiedu, Berchie; K. K. Amponsah, Samuel; A. Commey, Nii

doi:10.21608/ejabf.2020.109691

Some aspects of the biology of West African Ilisha (Ilisha africana, Bloch 1795) from the coast of Ghana, West Africa

Document Type : Original Article

Authors

10.21608/ejabf.2020.109691

Abstract

Some aspects of the reproductive biology of West Africa Ilisha, I. africana in the coastal waters of Ghana, were studied between August 2018 and July 2019 to enhance sustainable management and exploitation. The mean length varied significantly with sex (12.8 ± 0.2 cm in males, 13.9 ± 0.3 cm in females). Condition factor (K) varied significantly with sex (0.70 ± 0.01 in males, 0.73 ± 0.02 in females). The growth pattern for males and females was 2.93 and 3.02, respectively. The sex ratio of 1.3 male: 1.0 female was observed which deviated significantly from the theoretical 1 male: 1 female ratio, indicating that males were significantly more than females (X²=14.0, df = 6; P = 0.029). The GSI varied significantly with sex throughout the study (2.29 ± 0.30 in males), (3.94 ± 0.25 in females). Five maturity stages were recorded for both males and females. The spawning period for males was August – December whereas in females, the spawning period was August – January. The length at first maturity for females and males was 16.0 cm and 15.9 cm, respectively. Fisheries management strategies such as closed fishing season should take into account the major spawning season to ensure the full realization of its objective which is to preserve the fish stocks in Ghana’s waters and exploitation within biologically acceptable levels.

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