Re-validation of biochemophysical variables as metrics for assessing the ecological integrity of an aquatic ecosystem (Badagry Lagoon, Lagos, Nigeria)

Abstract

Assessment of ecological integrity of aquatic ecosystem is a major priority for scientists, government and private concerns all-over the world. In this study, multi-metric indices (physico-chemistry, biodiversity, length–weight relationship and condition factor) was used to evaluate the ecological integrity of Badagry Lagoon, Lagos, Nigeria. Three sampling sites (Akarakumo, Topo and Ajido) were selected based on extent of fishing activities. Water and fish samples were collected monthly from the three sampling stations for ten consecutive months (February to November, 2018). Standard methods were used for the analysis of physico-chemical parameters, fish diversity, length–weight relationship and condition factor of some fish species from the study sites. Simpson’s dominance index (0.056–0.057) and Shannon diversity index (3.11–3.13) were similar for the three sampling stations. The initial growth coefficient (a) in this study varied within a very narrow range (0.01–0.04) while the growth coefficient (b) had wider range (2.14–3.16). Growth pattern was predominantly negative allometry. Most of the fish species encountered were not under threat of extinction except Sarotherodon melanotheron and Sarotherodon galilaeus that were critically endangered and vulnerable, respectively. The physico-chemical variables of the sampling stations indicated that the ecological integrity of the water body is high, and this was corroborated by the results of biodiversity study, length–weight relationship and condition factors. Therefore, these metrics can be used in the assessment of the ecological integrity of aquatics.