Assessment of Growth and Mortality Parameters of Four Commercial Fish Species from Lekki Lagoon Nigeria

Abstract

This study assessed the growth and mortality parameters of four commercial fish species (Chrysichthys ni-grodigitatus (Lacepède, 1803), Coptodon zillii (Gervais, 1848), Ethmalosa fimbriata (Bowdich, 1825) and Elops lacerta (Valenciennes, 1847) from Lekki Lagoon, Nigeria. Fish specimens were collected monthly from five landing sites (Wharf, Agbalegiyo, Ebute-Oni, Ilumofin and Luboye). Specimens were collected us-ing proportional sampling based on the level of fishing activities between January and December, 2022. Es-timation of growth parameters was performed according to the growth equation: Lt = L∞- (1- e-K(t-to)) by von Bertalanffy with the Length Frequency Data Analysis (LFDA) package. The length-converted catch curve model was adopted for the estimation of mortality parameters using FiSAT II software. Results showed that C. nigrodigitatus exhibited the highest growth rate (K = 1.30 yr⁻¹) and exploitation rate (E = 0.83) with an as-ymptotic length (L∞) of 53.94 cm. However, C. zillii exhibits the lowest growth curvature (K = 0.44 yr⁻¹) with L∞ = 39.15 cm and an exploitation rate of 0.42. E. fimbriata showed a rapid growth rate (K = 1.15 yr⁻¹) but low exploitation (E = 0.12), while E. lacerta exhibited moderate growth rate (K = 0.58 yr⁻¹) and low exploita-tion (E = 0.16). It is concluded that C. nigrodigitatus is overfished in the lagoon, which demands a closed season and small mesh size restriction to prevent recruitment overfishing. The low exploitation levels of E. fimbriata and E. lacerta means that these stocks are currently sustainable, but there is a need to monitor them to avoid future over-exploitation.