BENTHIC FEATURES OF CORAL PATCH REEFS AND ITS IMPACT ON THE ABUNDANCE OF THE TRICOLOR PARROTFISH (SCARUS TRICOLOR) IN SOLONG-ON LAGOON, SIQUIJOR ISLAND, PHILIPPINES

Abstract

Reef patches are typically small, sheltered coral aggregations that often host high abundance and diversity of reef fish, many of which spend only part of their life-cycle (often during their juvenile stages) before returning to the coral reef as adults, and one good example is Parrotfish (e.g. Scarus tricolor). This species has been aimed at local artisanal fishing. However, very little information is available in the literature on the ecology of this species (especially during its juvenile stage) and on the function of back-reef nursery habitat characteristics (benthic features). Between March and May 2019, benthic surveys quantified 11 benthic features of the reef patches in the Solong-on Lagoon.The relationship between benthic features has been visualized using the Principal Component Analysis (PCA). Multicollinearity with a threshold of 10 was avoided by the use of the variance-inflation factor (vif) test. The predictor variables were selected using the Generalized Linear Model (GLM) against the abundance of S. Tricolor as the variable of response. Reef scale requires a mean diameter and a surface area of between 3.65-19.25 m and 96.08-1484.21 m2. Reef difficulty varies from medium-very high vertical relief, 1.5-3.5 slope and 1.07-1.70 roughness. PCA has shown that the reef surface area, dead corals and live hard corals are the most influential variables between reef patches.The mean fish abundance ranged from 0.33 to 13.33 individuals / m2 and did not differ significantly between months and sampling sites. Of the eight independent variables (benthic characteristics) modeled using GLM, two variables (reef patch size and dead coral cover) were found to significantly predict the abundance of S.tricolor.