Community structure and size-frequency distribution of soft corals in a heavily disturbed reef system in northwestern Philippines

Abstract

Soft corals in the Philippines have received little attention. In this study, community structure and size-frequency distribution of soft corals were assessed via quantitative surveys in a heavily disturbed reef system in northwestern Philippines. Relationships between selected environmental parameters and benthic components were also investigated. Results reveal that soft coral cover, density, and taxa richness were lowest at stations nearest a fish farming area, characterized by the poorest water quality. Differences in dominance of taxonomic groups may indicate differences in environmental preference or tolerance. Exposure to waves and water clarity were determined to have high correlations with the distribution of different taxa. Symmetrical size distributions of selected alcyoniids were indicative of healthy populations. However, the negative skewness of Lobophytum may indicate an eventual population decline caused by unfavorable environmental conditions. The study's findings suggest the need to conduct a detailed analysis of the different soft coral variables during coral reef surveys to improve data interpretations necessary for coral reef management in the Philippines.