Growth and stock exploitation parameters of Sphyrna lewini (Griffith & Smith, 1834) living in the Ivorian coastal water

In Côte d’Ivoire, data on shark exploitation are limited to landing records. The high demand for fins in Asian markets has led to an increase in shark catches. Yet many species are threatened with extinction, despite their crucial role in maintaining the balance of marine ecosystems. This study aims to determine the growth parameters of Sphyrna lewini and to assess the level of stock exploitation off the Ivorian coast, in order to improve resource management. Between January 2019 and December 2020, the total length of 774 specimens between 90 and 235 cm was measured. From the length frequency data, growth and exploitation parameters were evaluated using FiSAT II software. The estimate reveals growth rate (K) at 0.17 year⁻¹, asymptotic length (L∞) at 266.75 cm, and growth performance index (Ø’) at 4.083. The species undergoes total mortality (Z) of 0.92 year⁻¹, natural mortality (M) of 0.29 year⁻¹, and fishing mortality (F) of 0.63 year⁻¹, resulting in an exploitation rate (E) of 0.68. The specimens caught are mostly small in size, with a higher catch abundance during the major cold season. The species is slow-growing. Sphyrna lewini’s stock in a state of overexploitation. Maintaining the current fishing pressure could lead to stock collapse. Further study on reproduction and ecology of Sphyrna lewini in Côte d’Ivoire is necessary to identify the periods and areas of reproduction, with a view to creating marine protected area.