Coral diseases on Philippine reefs: Genus Porites is a dominant host

Abstract

While it is generally assumed that Indo-Pacific reefs are not widely affected by diseases, limited data suggest a number of diseases and syndromes that appear to differ from those currently under study in the Caribbean. This report presents the results of a baseline survey of coral diseases in 2 regions in the Philippines: the Central Visayas and the Lingayen Gulf. Mean prevalence for all diseases observed was 8.3 ± 1.2 % (mean ± SE; n = 8 reefs), with Central Visayas reefs showing higher disease prevalence (11.6 ± 2.8 %; n = 4 reefs) than those of Lingayen Gulf (5.1 ± 1.4 %; n = 4 reefs). Five diseases and syndromes were described; 3 of these - Porites ulcerative white spot disease (PUWS) (prevalence = 8.96 ± 2.2 %), tumors (prevalence = 1.0 ± 0.5%) and pigmentation response (prevalence = 0.5 ± 0.2 %) - occurred frequently in both regions and targeted the genus Porites. Correlation between disease prevalence and number of Porites colonies was fairly strong (r2 = 43.4), though not significant, and no correlation was seen between prevalence and either the amount or diversity of hard coral. Porites is a major reef-builder in the Indo-Pacific comprising 30 % of hard coral colonies on our surveyed reefs, and is generally thought to be a hardy, long-lived genus. Diseases targeting this robust group present an as yet unquantified risk to Philippine reefs and could result in major changes in reef structure. © Inter-Research 2005.