Some anthropogenic noise is now considered pollution, with evidence building that noise from human activities such as transportation, construction and exploration can impact behaviour and physiology in a broad range of taxa. However, relatively little research has considered the effects of repeated or chronic noise; extended exposures may result in habituation or sensitisation, and thus changes in response. We conducted a field-based experiment at Moorea Island to investigate how repeated exposure to playback of motorboat noise affected a coral reef fish (Dascyllus trimaculatus). We found that juvenile D. trimaculatus increased hiding behaviour during motorboat noise after two days of repeated exposure, but no longer did so after one and two weeks of exposure. We also found that naïve individuals responded to playback of motorboat noise with elevated ventilation rates, but that this response was diminished after one and two weeks of repeated exposure. We found no strong evidence that baseline blood cortisol levels, growth or body condition were affected by three weeks of repeated motorboat-noise playback. Our study reveals the importance of considering how tolerance levels may change over time, rather than simply extrapolating from results of short-term studies, if we are to make decisions about regulation and mitigation.

Coral colony size-frequency distributions can be used to assess population responses to local environmental conditions and disturbances. In this study, we surveyed juvenile pocilloporids, herbivorous fish densities, and algal cover in the central and southern Saudi Arabian Red Sea. We sampled nine reefs with different disturbance histories along a north–south natural gradient of physicochemical conditions (higher salinity and wider temperature fluctuations in the north, and higher turbidity and productivity in the south). Since coral populations with negatively skewed size-frequency distributions have been associated with unfavorable environmental conditions, we expected to find more negative distributions in the southern Red Sea, where corals are potentially experiencing suboptimal conditions. Although juvenile coral and parrotfish densities differed significantly between the two regions, mean colony size and size-frequency distributions did not. Results suggest that pocilloporid colony size-frequency distribution may not be an accurate indicator of differences in biological or oceanographic conditions in the Red Sea.

Oman contains diverse and abundant reef coral communities that extend along a coast that borders three environmentally distinct water bodies, with corals existing under unique and often stressful environmental conditions. In recent years Oman's reefs have undergone considerable change due to recurrent predatory starfish outbreaks, cyclone damage, harmful algal blooms, and other stressors. In this review we summarize current knowledge of the biology and status of corals in Oman, particularly in light of recent stressors and projected future threats, and examine current reef management practices. Oman's coral communities occur in marginal environmental conditions for reefs, and hence are quite vulnerable to anthropogenic effects. We recommend a focus on developing conservation-oriented coral research to guide proactive management and expansion of the number and size of designated protected areas in Oman, particularly those associated with critical coral habitat.

2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine (Irgarol-1051) has been widely used as effective alternative antifouling paint in marine structures including ships. However, it has been causing deleterious effects to marine organisms including reef building corals. The main objective of this study was to establish baseline levels of Irgarol-1051 around coral reefs and nearby ecosystems along coastline of Zanzibar Island. The levels of Irgarol-1051 ranged from 1.35ng/L around coral reefs to 15.44ng/L around harbor with average concentration of 4.11 (mean)±0.57 (SD) ng/L. This is below Environmental Risk Limit of 24ng/L as proposed by Dutch Authorities which suggests that the contamination is not alarming especially for coral reef ecosystem health. The main possible sources of the contamination are from shipping activities. This paper provides important baseline information of Irgarol-1051 around the coral reef ecosystems within the Western Indian Ocean (WIO) region and may be useful for formulation of marine conservation strategies and policies.

Trinidad and Tobago was the last Caribbean island to be invaded by the lionfish and since its invasion in 2012 they have spread to most coral reef and hard bottom environments. Standard reef fish surveys were used to assess lionfish population densities and size distributions from 2013–2015. Total lengths ranged between 6.2–40.4cm and 2.2–950g in weight. The length-weight relationship was described by W=0.0002L2.5654. Fish densities were highest in the northeast Tobago at 326lionfish/ha and the lowest in the southwest Tobago at 10.5lionfish/ha. In order to curtail the spread of this invasive species, a culling programme was initiated at selected reefs to regularly remove lionfish at monthly intervals. On the selected reefs 26–30% reduction in mean lionfish biomass and 25–27% reduction in abundance was noted compared to control sites (p<0.05).

Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay–Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters.

Jakarta Bay, next to the Jakarta Metropolitan Area with around 30 million inhabitants, is facing extreme pollution. Although local coral reefs are degraded and marine resources heavily exploited, they provide livelihoods for millions of people. This study investigates anthropogenic pressures on local fisheries resources and associated livelihoods. Questionnaire surveys were conducted in 15 coastal communities (10 coastal neighborhoods in Jakarta Bay on the mainland and 5 of the offshore Thousand Islands). The most economically valuable species were Caesio cuning (Redbelly yellowtail fusilier) on the islands and Rastrelliger kanagurta (Indian mackerel) on the mainland. Over 80% of all interviewed fishermen regarded the current state of marine resources as declining, mainly due to pollution and overexploitation. While perceptions of declining resources were equally high on the islands and the mainland, pollution was listed as the principal cause of degradation significantly more on the mainland. Findings are discussed in the context of coastal livelihood vulnerability.

Internal macrobioeroders and their erosion rate in three live and dead coral genera (Favia, Platygyra and Porites) from the intertidal zone of the Hormuz Island were studied by collecting five live and five dead colonies from each genus, from which 4mm cross-sections were cut and photographed. Photos were analyzed using the Coral Point Count with Excel extensions. Totally, 9 taxa were identified: four bivalve species, one sponge, three polychaetes, and one barnacle. Bioerosion rate did not significantly differ among the three live corals, but among the dead ones only Porites was significantly more eroded than Favia. Sponge had the highest role in the erosion of the dead Platygyra, while barnacles were the most effective eroding organism in the live Platygyra. Polychaetes, followed by bivalves, were the most destructive bioeroders on the dead and live Porites. Further, none of the bioeroding organisms had selectively chosen either the dead or live Favia.

Elevated sediment loads within the epilithic algal matrix (EAM) of coral reefs can increase coral mortality and inhibit herbivory. Yet the composition, distribution and temporal variability of EAM sediment loads are poorly known, especially on inshore reefs. This study quantified EAM sediment loads (including organic particulates) and algal length across the reef profile of two bays at Orpheus Island (inner-shelf Great Barrier Reef) over a six month period. We examined the total sediment mass, organic load, carbonate and silicate content, and the particle sizes of EAM sediments. Throughout the study period, all EAM sediment variables exhibited marked variation among reef zones. However, EAM sediment loads and algal length were consistent between bays and over time, despite major seasonal variation in climate including a severe tropical cyclone. This study provides a comprehensive description of EAM sediments on inshore reefs and highlights the exceptional temporal stability of EAM sediments on coral reefs.

It is suspected that land cover alteration on the southern coast of St. Thomas, USVI has increased runoff, degrading nearshore water quality and coral reef health. Chronic and acute changes in water quality, sediment deposition, and coral health metrics were assessed in three zones based upon perceived degree of human influence. Chlorophyll (p<0.0001) and turbidity (p=0.0113) were significantly higher in nearshore zones and in the high impact zone during heavy precipitation. Net sediment deposition and terrigenous content increased in nearshore zones during periods of greater precipitation and port activity. Macroalgae overgrowth significantly increased along a gradient of decreasing water quality (p<0.0001). Coral bleaching in all zones peaked in November with a regional thermal stress event (p<0.0001). However, mean bleaching prevalence was significantly greater in the most impacted zone compared to the offshore zone (p=0.0396), suggesting a link between declining water quality and bleaching severity.