Abundance and diversity of reef fish species and their relationship with corals along the eastern coast of Sri Lanka

Reef fish perform multiple ecological roles that are important for maintaining the structure and function of coral reefs. Reef fish assemblage patterns can be affected by natural and anthropogenic disruptions that change the structure of coral reef ecosystems. Our study aimed to understand the reef fish abundance, diversity, and relationships between reef fish families and coral families at five major coral reef ecosystems on the Eastern coast of Sri Lanka. In total, 272 reef fish species and 101 coral species were recorded. The highest and lowest relative abundance of fish was recorded at the Kayankerni (KR) and Adukkuparu reefs (AR) respectively. Pigeon Island Reef (PIR) had the highest fish diversity, evenness, and species richness followed by Parrot Rock Reef (PRR). Passikudah Reef (PR) had the lowest fish diversity indices and richness, but KR had the lowest fish evenness. In contrast, PRR had the uppermost percentage of live coral cover, coral diversity, evenness, and species richness. Coral species richness and live coral cover were lowest at the PR and AR respectively. The evenness of coral was lowest at PIR and the lowest Shannon-Weiner diversity was recorded at the AR. Reef fish family Lutjanidae and coral families Dendrophyllidae, Alcyoniidae, Plumulariidae, Mussidae, and Poritidae had a strong positive relationship. Coral family Acroporidae had a moderately positive relationship with fish families Pomacentridae and Pomoacanthidae. Overall, our results provide a comprehensive outlook of coral reef, reef fish diversity, and their relationship along the eastern coast of Sri Lanka.