Epidemiologi penyakit karang sabuk hitam (Black Band Disease) di Kepulauan Seribu, Jakarta

Abstract

Coral diseases that have emerged since the early 1970s with finding the Black Band Disease. Coral disease have caused significant regional ecological impacts. However, there has been a paucity of research into coral disease in South-East Asia, including Indonesia. This study provides baseline coral disease data in the Kepulauan Seribu Marine National Park. Previously only one type of disease (White Syndrome, WS) has been detected at this site. The coral disease data which successed provided were distribution and abundance, prevalence, incidence and progression of BBD within the Kepulauan Seribu region, and a Marine National Park as spatially from the nearest sites (zone 1), middle sites (zone 2) and the farthest sites (zone 3) from the mainland of Java Island. Research on the abundance and distribution of coral disease has been implemented on 12 sites spatially with 1 survey since June-July 2011, whereas prevalence, incidence of BBD carried out on 6 permanent sites for 1 year started from June 2011-March 2012 as representative of 1 cycle of the seasons (dry, transition 1, rain, transition 2). The research carried out by using line intercept transect (LIT) with 3x20 m to know the coral condition on upper reef slope, then continued by belt transect on the same place with 2x20m and 3 replicates. Total area coverage is 120 m2. The coral disease progress carried out on zone 1 and zone 2. Especially on the BBD peak season, the survey was carried out at reef slope (8 sites) to get BBD prevalence to know the BBD prevalence on different depths. The results showed that coral diseases of BBD found in mostly on the high life coral cover and especially on the coral Montipora sp species dominantly at that location. This study showed a positive correlation between overall coral cover and the dominant reef building coral Montipora spp on the research sites and found two main diseases BBD and WS which were highly prevalent throughout all locations. Based on spatial location of the abundance average, the highest abundance of BBD (0.08 col. m-2, n=3) was found at zone 1, whilst for WS (0.05 col.m-2, n=5) highest abundance was found at zone 2. BBD abundance was characterized by the higher of the life coral cover of scleractinian and Montipora spp, colony number of corals and especially Montipora spp. The survey for one year (one cycle of the seasons) found both BBD 1549 colonies and other type of disease 356 colonies during the study. BBD was found to be the most prevalent disease, ranging from 0.31% to 31.64%. Highest average prevalence was found at zone 2 (6.31%), followed by zone 3 (5.76%), with zone 1 having the lowest average prevalence at 3.76%. Due to prevalence being lowest at zone 1, it is unlikely that anthropogenic sources from the mainland are responsible for increased BBD prevalence. Data from temporal surveys revealed BBD abundance was highest during the transitional time which was the period between dry and rainy seasons (10.17%), followed by rainy season (4.88%) and dry season (4.26%). BBD incidence was happen at the same role with the BBD prevalence but the value at the highest (3.18%) in zone 2, followed by zone 3 (1.67%) and zone 1 (3.18%). BBD progression was highest on at zone 2 (8.10%) and zone 1 (3.79%). The highest rate of BBD progression occurred during dry seasons as temperatures and light intensity sharply increased during this time. BBD prevalence was higher on the upper reef slope than the reef slope, due to temperature and light intensity being having a greater impact at shallower depths. Black band disease was found to occur mainly in Montipora spp, but it is worth noting that this genus also makes up the majority of coral species found at the study sites, upper reef slope. The highest abundance on the zone 1 happened in dry season that the current with anthropogenic waste moved from the mainland to the islands in Kepulauan Seribu. Moreover the temperature average ranged from 28.98 - 29.39 °C known as optimum temperature for patogen bacteria infection of BBD. During this outbreak event occurring at the transitional time in November 2011, there were increasing parameters such as temperature, light intensity, Ortho-phosphate, while TOM (Total Organic Matter), turbidity and current were found decreasing. These decrease parameters caused light intensity can reach optimally to sea bottom. Meteorologi data of rainfall and wind speed showed decreasing, while the duration of sun shine and air temperature were increasing. These parameters were suitable with sea temperature and light intensity were increasing that made coral become stress and were easily infected by bacteria patogen. Bacterial communities associated with infected coral were found Bacillus sp dan Desulfovibrio spp, and health sample found Halomonas sp, Shewanella spp and Vibrio fischeri. Dominant bacteria were no found on dead samples. Coral tissue based on microscopic observation was not able to identify on dead sample. Bacteria communities on infected, health and dead coral showed the similarity of each sample among different zone of research sites.