Determination of the age and growth of Brachydeuterus auritus from Togolese waters by Otolithometry

Résumé

The present study aims to estimate age and growth parameters of Brachydeuterus auritus, catched by Togolese marine artisanal fisheries, to be used for stock assessment.

Methodology and results: The otoliths were extracted from commercial landings by Togolese marine fisheries and analyzed in the Tenerife IEO (Instituto Español de Oceanografía) laboratories. The results showed that Total Length of the fish (T_L) is linked to the otolith weight (OW): T_L = 5.171*ln (OW) + 28.805 (R²=0.9227). The mean length by age-class from the Age-Length key for the age-classes 1 to 4 were 10.6, 13.2, 15.1 and 16.8 cm, respectively.  Length and age data were fitted to von Bertalanffy equation, and the growth parameters estimated were L_∞ 23.15 cm; k  0.225 year^-1 and t₀ -1.722 year.

Conclusion and results applications: The present results, comparable globally to those obtained in West centre of Gulf of Guinea by other methods, are much close to Beck (1974) results in Togo waters using marking and recapture method. Therefore, these results could be useful for the stock assessment of this species from Togo waters.