Coral community structure in Tioman Island Marine Park, Malaysia : further emphasis on hard coral disease and pathogenic Vibrio spp.

Abstract

Tioman Island has a remarkably high coral diversity. Hence, evaluating the coral health status in this Marine Park is important for sustainable reef ecosystem management. This study aims to determine the reef condition, coral distribution and disease prevalence using Coral Video Transect (CVT) method at twenty reef sites and two different depths around the east coast, west coast and the isolated zones of Tioman Island Marine Park (TIMP). Coral Point Count with Excel extension (CPCe) software was used to measure the coral coverage and disease prevalence. The present results indicated that Tioman reefs were in ‘fair’ average condition with the live corals cover 48.0% ± 0.7. Besides, 254 species from 61 genera and 15 families of the scleractinian hard corals were identified at all reef sites. Following the scleractinian taxonomic classification, coral surveys and past studies revealed 355 species from 67 genera and 15 families with an additional 30 new species records for TIMP and 15 species for the east coast of Peninsular Malaysia. Current data at this island also presented 29 rare, 86 vulnerable, 3 endangered scleractinian species. Moreover, visual photographic analysis using the CPCe software was recorded 77 genera from 24 families of hard and soft corals with mixed morphologies of branching Acropora, foliose Montipora and massive Porites corals predominantly found in reef assemblages. Extensive coastal development and widespread of tourism activities may have influenced on the variations of reef condition and coral distribution in the study area. In addition to coral disease prevalence, the findings showed lower severity of diseased (5.8% ± 0.8) and compromised (28.8% ± 2.5) compared to healthy (65.4% ± 2.6) coral colonies in TIMP. Reef sites with the highest concentration of tourism exhibited a high prevalence of coral diseases and signs of compromised health. Among the six identified coral diseases, yellow band disease/ YBD (1.70% ± 0.8) had the highest prevalence followed by ulcerative white spots/ UWS (1.14% ± 0.2) and white syndrome/ WS (1.08% ± 0.3). Meanwhile, algal and sponge overgrowth/ ASO (11.86% ± 2.3), sediment necrosis/ SN (7.05% ± 0.9), predation scars/ PS (5.60% ± 0.8) and physical damage/ PD (2.06% ± 0.8) were the most prevalence among eight identified states of coral compromised health. Altogether, 33 scleractinian genera were affected, with Fungia predominantly affected by YBD (> 30% colonies), while Porites and Acropora were affected by UWS and WS (11 - 20% colonies), respectively. In continuation, the pathogenic Vibrio spp. isolated from WS infected corals (Acropora and Montipora) were identified using biochemical and molecular techniques. The infected coral tissues were confirmed based on the histological examination. A total of one hundred representative Vibrio isolates were characterized and most of them (n = 50) were identified as V. vulnificus, V. alginolyticus and Photobacterium damselae following the API 20NE kit. The 16S rRNA gene sequencing revealed six Vibrio spp. (V. coralliilyticus, V. hepatarius, V. brasiliensis, V. tubiashi, V. campbellii and V. ishigakensis) and one P. rosenbergii. V. coralliilyticus, isolated from the infected corals also had the highest mean prevalence (45.4% ± 6.7) at three selected reef sites in TIMP. Such elevated of water temperatures and nutrient parameters may increase the Vibrio bacterial prevalence. As a conclusion, the data presented in this study constitutes the baseline information on coral health and disease prevalence, including the possible causal agents associated with WS disease sign for comprehensive coral conservation in the marine protected area of Tioman Island.