Explore the vast range of titles available.

HighlightsCoral cover, rugosity, and reef fish abundance was determinedThe relationship between coral cover and rugosity and fish abundance was analyzed.Coral cover in East Java were categorized as medium – good.The rugosity index and the fish abundance were highest in Bangsring Waters.There are no relationships between coral cover and fish abundance, but there is relationship between rugosity and fish abundance.AbstractA coral reef is one of the most complex and specific ecosystems in a tropical area. It is identified by its high productivity and biodiversity. This research aims to discover the percentage of coral reef cover and rugosity, as well as the fish abundance in several locations in East Java, Indonesia. In addition, this research aims to investigate the correlation of coral reef cover and rugosity with the density of coral reef fish. This research was conducted in three locations, i.e., Bangsring Waters of Wongsorejo District, Banyuwangi Regency; Gili Noko Bawean Island, Gresik Regency; and Kramat Island, Gili Genting District, Sumenep Regency. This research employed the Line Intercept Transect (LIT) method to calculate the percentage of coral reef cover, the Chain Intercept Transect (CIT) method to determine the coral reef rugosity, and the Belt Transect method to estimate the fish abundance. From this research, it was revealed that the highest coral reef cover was in Bawean waters, while the highest rugosity was in Bangring waters. In addition, the highest coral reef fish density was in Bangsring waters. Meanwhile, the coral reef fish density did not correlate with the percentage of coral reef cover. In contrast, it correlated with the coral reef rugosity. 

The Caribbean coral reef ecosystem has experienced a long history of deterioration due to various stressors. For instance, over-fishing of parrotfish – an important grazer of macroalgae that can prevent destructive overgrowth of macroalgae – has threatened reef ecosystems in recent decades and stimulated conservation efforts such as the formation of marine protected areas. Here we develop a mathematical model of coupled socio-ecological interactions between reef dynamics and conservation opinion dynamics to better understand how natural and human factors interact individually and in combination to determine coral reef cover. We find that the coupling opinion and reef systems generates complex dynamics that are difficult to anticipate without use of a model. For instance, instead of converging to a stable state of constant coral cover and conservationist opinion, the system can oscillate between low and high live coral cover as human opinion oscillates in a boom-bust cycle between complacency and concern. Out of various possible parameter manipulations, we also find that raising awareness of coral reef endangerment best avoids counter-productive nonlinear feedbacks and always increases and stabilizes live coral reef cover. In conclusion, an improved understanding of coupled opinion-reef dynamics under anthrogenic stressors is possible using coupled socio-ecological models, and such models should be further researched.

This study examines the morphodynamic evolution of the shoreline and coral reef coverage along the Arabian Sea coast of Oman over the past five decades (1972–2022). The Peninsula of Bar Al Hikman, the largest low-lying coastal area in Oman (550 km 2 ; elevations < 10 m), hosts unique, monospecific coral reefs developing under a monsoon climate. Unlike other densely populated, low-lying coastal areas in the Middle East (e.g., the Gulf), the southern Arabian Plate has received limited attention, with few studies addressing its coastal evolution or future environmental risks. By combining sedimentological fieldwork with photo-interpretations of satellite images spanning 50 years, this study documents significant coastal geomorphological changes. The findings reveal a dramatic 60% reduction in the surface area of Bar Al Hikman’s main coral reefs. A significant consequence of this reef shrinkage is the rapid shoreline erosion on the leeward side of the disappearing reefs. Half of the southern shoreline of the peninsula is retreating northward at rates exceeding 1 m/year, with localized section (6%) eroding at extreme rates of over 10 m/year. At this pace, the ongoing reef decline is likely to exacerbate shoreline erosion, accelerate the landward migration of barrier bars and in turn close off lagoonal areas, and threaten intertidal ecosystems. Furthermore, with the ongoing global rise in sea level, a substantial portion of the peninsula is predicted to fall below the annual flood limit by 2050. This will result in the extensive landward migration of coastal sabkhas deeper into the peninsula's interior. Overall, this study provides a baseline for understanding the recent evolution of Oman’s Arabian Sea coastline and underscores the importance of developing policies and coastal management strategies to mitigate the effects of ongoing environmental and sea-level changes.

Abstract This study aims to determine the percentage of coral reefs with extensive closure Biorock method and determine the relationship between the percentage of closure on the abundance of fish species in the area of rehabilitation with Biorock method. The study was conducted at two locations, locations with Biorock and natural reefs (Reef Seen). Research carried out by using the line transect method or Point Intercept Transect (PIT) with a direct enumeration technique Cencus Visual Method (VCM) and photo transects for data reef fish and coral reef data. Transects installed in locations that have been selected, the depth of 8 m. The main parameters studied, namely the abundance of coral and fish species identified at the sites. Supporting the studied parameters of physical and chemical parameters of waters, including: temperature, salinity, water pH and brightness and the percentage cover of coral. Measurement of water quality, including: temperature, depth, salinity, acidity and brightness. The results of this research is vast percentage of coral cover on the location Biorock of 38.5% with the type of branching Acropora growth, while at the location of Reef Seen by 43.5% to the type of hard coral growth form of corals that dominate submasif. The percentage of coral cover has no influence on the abundance of species of reef fish in the territorial waters of Pemuteran, Bali.

An influential paradigm in coral reef ecology is that fishing causes trophic cascades through reef fish assemblages, resulting in reduced herbivory and thus benthic phase shifts from coral to algal dominance. Few long-term field tests exist of how fishing affects the trophic structure of coral reef fish assemblages, and how such changes affect the benthos. Alternatively, benthic change itself may drive the trophic structure of reef fish assemblages. Reef fish trophic structure and benthic cover were quantified almost annually from 1983 to 2014 at two small Philippine islands (Apo, Sumilon). At each island a No-Take Marine Reserve (NTMR) site and a site open to subsistence reef fishing were monitored. Thirteen trophic groups were identified. Large planktivores often accounted for >50% of assemblage biomass. Significant NTMR effects were detected at each island for total fish biomass, but for only 2 of 13 trophic components: generalist large predators and large planktivores. Fishing-induced changes in biomass of these components had no effect on live hard coral (HC) cover. In contrast, HC cover affected biomass of 11 of 13 trophic components significantly. Positive associations with HC cover were detected for total fish biomass, generalist large predators, piscivores, obligate coral feeders, large planktivores, and small planktivores. Negative associations with HC cover were detected for large benthic foragers, detritivores, excavators, scrapers, and sand feeders. These associations of fish biomass to HC cover were most clear when environmental disturbances (e.g., coral bleaching, typhoons) reduced HC cover, often quickly (1–2 yr), and when HC recovered, often slowly (5–10 yr). As HC cover changed, the biomass of 11 trophic components of the fish assemblage changed. Benthic and fish assemblages were distinct at all sites from the outset, remaining so for 31 yr, despite differences in fishing pressure and disturbance history. HC cover alone explained ~30% of the variability in reef fish trophic structure, whereas fishing alone explained 24%. Furthermore, HC cover affected more trophic groups more strongly than fishing. Management of coral reefs must include measures to maintain coral reef habitats, not just measures to reduce fishing by NTMRs.

Most comparative studies assessing reef health focus on living hard coral cover as the key metric. In Indonesia, in situ monitoring of coral cover has been ongoing for over five decades. However, as monitoring data and research findings are predominantly published in the local language (Bahasa Indonesia), local data often escape global attention, resulting in Indonesian coral reefs receiving less scientific attention despite accounting for ~ 15% of all coral reef area globally. Here, we systematically compiled both globally and locally published data on coral cover across Indonesia to assess changes over recent decades. We analysed 7,614 data entries extracted from 621 publications and found that the majority (79.1%) of the publications were written in Bahasa Indonesia, constituting 63.4% of the total data entries. Our dataset revealed limited evidence of net declines in coral cover over the last three decades (1994–2022). There was also no clear relationship between coral cover and human density, as well as with the thirteen environmental/anthropogenic drivers examined. We discuss several factors that may contribute to this lack of detectable large-scale change including: recent data potentially representing a ‘shifted baseline’; the ‘averaging out’ of localised changes in coral cover dynamics at a broad scale; sampling biases; and/or the potential resilience of Indonesian coral reefs compared to other regions. This study highlights the wealth of accessible local coral reef data published in languages other than English and emphasises the importance of using such data to enhance our understanding of the long-term dynamics of coral reef ecosystems worldwide.

Mass bleaching events are growing in duration and intensity. Besides causing extensive mortality, the progressively shorter time between events disrupts the ability of reefs to recover. The unique reefs of the Southwestern Atlantic are often considered climate refugia as they have suffered less bleaching-related mortality when compared to Indo–Pacific and Caribbean reefs. However, their recovery capacity still requires investigation. In 2019, an unprecedented heatwave triggered the most severe bleaching episode recorded for Southwestern Atlantic reefs. Therefore, this study aimed to (i) document the bleaching incidence and mortality during the heatwave, and (ii) assess coral recovery over 3 years. We measured bleaching incidence and monitored coral cover through surveys in three Southern Bahia (central Brazilian coast) reefs before, during and after thermal stress. Our findings show that coral assemblages were exposed to a 5-month-long thermal anomaly, experiencing thermal stress peaking at 14.1 ºC-weeks. Roughly 70% of the coral cover was bleached, resulting in a decline of ~ 40%. Millepora alcicornis , Mussismilia braziliensis , and Mussismilia harttii were among species that mortality exceeded 50%. After 3 years, corals showed no increase in cover neither at assemblage nor species levels. This constrained recovery capacity may indicate the breakdown of the refugium, and also trade-off for resistance. Typical features of the region, such as high turbidity and the dominance of massive corals, provide these reefs with bleaching resistance, but likely also limit their recovery. With the anticipated effects of the 2023–24 El Niño–Southern Oscillation in the southern hemisphere, still unrecovered Southwestern Atlantic reefs face a substantial challenge.

Cycles of disturbance and recovery govern the temporal dynamics of living coral cover on coral reefs. Monitoring the state of the Great Barrier Reef at regional and individual reef scales has been ongoing by the Long-Term Monitoring Program at the Australian Institute of Marine Science since 1986. After a period of relative stability between 1986 and 2010, the latest decade of surveys recorded increased frequency of intense, large-scale disturbance events and coral cover has reached unprecedented lows and highs in each region. Following the consecutive bleaching events in 2016 and 2017, widespread recovery occurred on the northern and central Great Barrier Reef between 2017 and 2022, which was halted in 2023. An examination of the effects of the 2022 bleaching event revealed that the direct and indirect impacts of this event, along with ongoing crown-of-thorns starfish outbreaks, notable incidences of coral disease, and the passage of a tropical cyclone all contributed to the most recent coral cover changes across the Great Barrier Reef. The prognosis for future disturbances suggests increasing and longer-lasting marine heatwaves, continuing severe tropical cyclones and the ongoing risk of outbreaks of crown-of-thorns starfish. Although the observed capacity for recovery is a cause for cautious optimism for the overall state of the Great Barrier Reef, there is increasing concern for its ability to continue to bounce back in the face of escalating climatic pressure.

Isolated coral reef habitats are unique systems to study the natural dynamics of coral traits and their natural acclimatization, adaptation, and recovery from global-scale stressors such as thermally induced bleaching events. This study evaluates the spatial and temporal changes in coral community attributes (diversity, live cover, and coral assemblage structure) over 14 years (2005–2019) at Clipperton, an extremely remote Eastern Tropical Pacific (ETP) atoll. The atoll exhibited overall high coral cover (~ 50–60%) dominated by massive species (Porites spp.), yet we observed large variation (44–56%) in coral community attributes among survey years (2005, 2016, 2019) with depth explaining most of the variation. Live coral cover increased in 2019 after a severe thermal stress event (El Niño, 2015–2016) and many tropical cyclones, which also caused a shift in assemblage structure from branching Pocillopora to massive Porites in the shallower reef zones, resulting in a less well-defined depth gradient. These changes in coral assemblage structure may have long-term effects on the configuration of the physical reef framework of the well-conserved coral reef ecosystems at Clipperton and consequently may alter the ecological functionality of one of the most important biogeographic stepping stones in the central Pacific and ETP regions.

The structural complexity of coral reef environments has a strong influence on the assemblage of reef-associated fishes and invertebrates. These unique ecosystems provide these reef-associated species with a broad range of potential habitats, which offer important resources such as food and shelter. The most studied habitat association on reefs is that of hard coral and fish, where hard coral cover has been found to have a large and positive influence on the assemblage of reef fishes. In contrast, soft coral has been considered poor habitat due to their chemical defences and weak body architecture. However, the empirical basis for this assumption is minimal and the ecological importance of soft corals remains controversial and unresolved. The present study closely examined fish assemblages utilising a mixed mosaic of coral reef habitats at sites ranging from hard to soft coral dominated assemblages. Fishes associated with soft coral in a variety of ways including as shelter, a source of food or a surface on which epiphytic food was sourced. Fish assemblages remained similar between soft and hard coral dominated habitats, and there was no evidence that a high percentage cover of soft coral had deleterious effects. Further, a significant increase in species richness of fishes was found with increasing soft coral cover, suggesting that the importance of soft coral habitat has been underestimated on reefs with a mosaic of different habitats. Here, we discuss the implications of these associations and suggest that soft coral provides distinct habitat for reef fishes, and future research should address their ecological importance.