Population parameters of barracuda, Sphyraena afra (Family: Sphyraenidae) from coastal waters of Lagos State, Nigeria

ABSTRACT

A better understanding of the population dynamics of exploited fishery resources requires information on growth parameters of the population studied. This study was carried out to determine the growth, mortality rate and exploitation rate of Sphyraena afra collected monthly between August 2009 and July 2011 from coastal waters of Lagos State to contribute to sustainable management of this fishery. Powell-Wetherall and ELEFAN 1 models in FAO-ICLARM Stock Assessment Tools (FiSAT) software were used to estimate population parameters which gave asymptotic length L∞, growth coefficient K, and performance index ф as 192.68 cm, 0.1, and 3.57, respectively. The estimated values of the instantaneous rate of total mortality, natural mortality, fishing mortality and exploitation rate were 1.29 year⁻¹, 0.24 year⁻¹, 1.05 year⁻¹, and 0.81, respectively. The total mortality of S. afra (1.29/year) suggests that the stock is dwindling, and an estimated Z/K ratio of 12.9 shows a predominance of mortality over growth indicative of the stock collapsing. Sphyraena afra recruits peaked twice per year suggesting that two spawning periods are likely. The exploitation rate for S. afra in the coastal waters of Lagos State was relatively high and exceeded the optimum value for sustainable yield for the exploitation of the fishery.

KEYWORDS:

• Sphyraena afra
• mortality
• growth parameters
• exploitation rate
• recruitment pattern

Acknowledgments

Our sincere gratitude to Nigerian Institute for Oceanography and Marine Research for providing funding and facilities to complete this study. We thank the reviewers for their constructive comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This paper was not funded.