Biodiversity of Coral Reef Fishes in the Coastal Waters of Eket, Akwa Ibom State

Coral reef fish assemblages are among the most diverse and ecologically important communities in tropical marine ecosystems, providing essential ecosystem services including nutrient cycling and food provision. This study investigated the biodiversity of coral reef associated fish species in the coastal waters off Eket, Akwa Ibom State, South South Nigeria. Underwater visual census surveys were conducted at four reef sites using belt transects of 25 by 4 metres during three sampling periods between January and June 2024. Fish species were identified in situ with reference to photographic field guides, and community parameters including species richness, abundance, and diversity indices were computed. Habitat quality assessments including percentage coral cover, rugosity, and substrate type were also recorded. A total of 73 fish species belonging to 31 families were documented. Pomacentridae, Labridae, and Chaetodontidae were the most species-rich families. Species richness was positively correlated with live coral cover and structural complexity. Sites with higher anthropogenic disturbance showed lower mean fish density and fewer functionally important herbivorous species. The fish assemblage at the reference site was significantly more diverse than at disturbed sites as determined by one-way ANOVA. The presence of indicator species such as Chaetodon species suggested moderately stressed reef conditions at most locations. This study provides foundational data for reef fish conservation planning and emphasises the need for no-take zone designations in the Eket coastal area. Keywords: coral reef fish, biodiversity, underwater visual census, Eket, Akwa Ibom.