91勛圖

Abstract

The valuation of biodiversity and environmental resources is important in understanding the healthy functioning of the environment. Diversity of fishes in Asejire Lake, Nigeria was studied for seven months (February to August, 2014). The lake was naturally divided into two strata-upper and lower reaches- one landing site in each stratum. Fish catches from fishermen were assessed, sorted into species, counted and weighed. Diversity indices package and cluster analysis were used for the statistical analysis. Twenty-four fish species from fourteen families were identified. Chrysichthys nigrodigitatus was the most abundant species by number (46.6%) and weight (34.3%) while Gnathonemus senegalensis was the least observed in the catch. Bagrid (46.7%) and cichlid (46.3%) families had the highest contribution by abundance and weight respectively. The greatest number of taxa was recorded in May and least in February. Lowest Simpson diversity index (0.50) was observed in February and highest in July (0.88). Simpson diversity index for the lake (0.70) was observed to be high with low dominance (0.30) and evenness (0.21). Cluster analysis showed six distinct groups of fish assemblages. Abundance-biomass comparison (ABC) curves revealed that Asejire Lake is a disturbed aquatic ecological system which might be attributed to over-exploitation of the fish resources in the lake and the waste discharge from the nearby industry. This may have negative implications on the fish production and conservation of the diverse species in the lake. There is need for monitoring and proper management of the lake system for sustainable fish production and conservation for the posterity.

Biography

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