Demographic characteristics and exploitation rate of Dormitator lebretonis (Pisces: Eleotridae: Steindachner, 1870) from four coastal lagoons of Southern Benin, West Africa

Abstract

Dormitator lebretonis (Pisces: Eleotridae) is the dominant eleotrid in the Benin coastal waters, where this species constitutes an important fisheries component. The current fisheries survey investigates demographic parameters and the exploitation of D. lebretonis from the Benin coastal waters to contribute to species conservation and sustainable use. Individuals of D. lebretonis have been sampled monthly for 18 months at four locations in the Benin coastal waters. Overall, D. lebretonis showed moderate asymptotic length (L∞) ranging between 11.55-12.08 cm. The growth rate (K) ranged between 0.74yr-1 and 3.1yr-1. The species exhibited moderate longevity ranging between 0.968 and 4.054 years. The growth performance index (φ’) varied between 1.994-2.617, indicating that D. lebretonis is a relatively slow-growing eleotrid. Annual mortalities dominate population growth (Z/K>1), and lengths at first capture (3.80≤L50≤5.05cm) indicated that D. lebretonis was exploited at immature stages. Nevertheless, the exploitation rate (E) was under 0.5, showing the stock was underexploited. The species showed two peaks of recruitment, except in Lake Ahémé. Sustainable exploitation of D. lebretonis in the coastal waters requires a holistic management scheme that should include fisheries regulation enforcement, spawning ground protection, ecosystem restoration, and follow-up.