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Clavularia inflata was first described from Ternate Island, Indonesia in 1896 and later reported appeared from Japan and Taiwan in 1953.Clavularia (Blainville 1830) soft corals exhibit complex morphological traits that are difficult to differentiate, thus complicating their identification. DNA barcoding has been envisioned and actively pushed as a credible method for assigning unidentified specimens to known species by comparison to a molecular reference data database. Thus, the purpose of this study was to use molecular methods to confirm the identity of 25 colonies taken from 13 Indonesian coral reef sites and putatively identified as Clavularia inflata. All specimens were identified as Clavularia inflata molecularly using the mitochondrial DNA mtMuts gene. Although a comparison of the nucleotide base chains to Genbank data indicates that the samples belong to a single species, two clades in the phylogenetic tree and data from the Automatic Barcode Gap Discovery (ABGD) indicate that there are two major groups of C. inflata in Indonesia, implying cryptic species.

Sustainably managing fisheries requires regular and reliable evaluation of stock status. However, most multispecies reef fisheries around the globe tend to be data-poor and lack research and monitoring capacity (e.g., long-term fishery data), preventing the estimation of sustainable reference points against which stocks can be assessed. Here, combining fish biomass data for more than 2000 coral reefs with catch estimates from 99 jurisdictions, we estimate site-specific sustainable reference points for coral reef fisheries and use these to assess the status of coral reef fish stocks. We reveal that more than half of jurisdictions with available information have stocks of conservation concern, having failed at least one fisheries sustainability benchmark. We quantify the trade-offs between biodiversity, mean fish length, and ecosystem functions relative to key benchmarks and highlight the ecological benefits of increasing sustainability. Our approach yields multispecies sustainable reference points for coral reef fisheries using environmental conditions, a promising means for enhancing the sustainability of the world’s coral reef fisheries.TeaserA global assessment of the sustainability of multispecies reef fisheries indicates that more than half of jurisdictions have failed at least one of two key sustainability benchmarks.

In recent decades, international assessments of the ocean have evolved from specialized, technical evaluations of the state of the marine environment to more integrated and thematically extensive science-policy platforms. As assessment programmes such as the UN Regular Process blossom on the global stage and subsume responsibility for tracking progress on sustainable development, there is a need to consider how their processes wield influence and effectively translate knowledge into action. In the present paper, we undertake a comprehensive review of the literature on global environmental assessments (GEAs) and extract key principles that can be applied to global assessments of the marine environment. We were particularly inspired to identify how social processes could be arranged to best distill, communicate, and produce actionable knowledge. While we look to the advice of experts in the literature, we highlight specific examples from the Intergovernmental Panel on Climate Change (IPCC), Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), and the Global Environment Outlook (GEO). From this review, knowledge coproduction, multilevel collaboration, and futures thinking emerged as the dominant principles of influential and action-oriented assessments. We conclude the paper by contextualizing how these principles may be operationalized for Global Marine Assessments in the future.

Human–nature interactions are at the root of sustainability problems worldwide. For the Indonesian coastal and marine realm, this chapter asks: How does governance affect, and how might it transform, human, and societal behavior in the coastal and marine realm toward greater ecological and social sustainability? Equipped with definitions of key social science terms (including governance, institutions, social–ecological systems), the reader is introduced to major changes, issues, and sectors in Indonesian coastal governance. Major policy recommendations at the end of subsections on the governance of (1) mangroves, (2) fisheries and aquaculture, (3) watersheds and land use, (4) marine and coastal conservation, (5) coastal livelihoods and social needs, and (6) pollution are presented. In line with the need for integrated planning, overlaps and trade-offs between these sectoral recommendations are identified and, within a theoretical framework of adaptive, evolutionary, and anticipatory governance, a set of generic suggestions for integrated inclusive governance approaches is proposed. Abstrak Interaksi antara manusia dan alam adalah dasar dari masalah keberlanjutan di seluruh dunia. Untuk wilayah pesisir dan laut Indonesia, bab ini bertanya: bagaimana pengaruh tata kelola, dan bagaimana hal itu mengubah perilaku manusia dan masyarakat di wilayah pesisir dan kelautan menuju keberlanjutan ekologis dan sosial yang lebih baik? Dilengkapi dengan definisi istilah utama ilmu sosial (termasuk tata kelola, lembaga, sistem sosial-ekologis), pembaca diperkenalkan dengan perubahan-perubahan, masalah dan sektor utama dalam tata kelola pesisir Indonesia. Di akhir subbagian, disajikan rekomendasi kebijakan utama tentang tata kelola dari 1. Hutan bakau, 2. Perikanan dan akuakultur, 3. Daerah aliran sungai dan penggunaan lahan, 4. Konservasi laut dan pesisir, 5. Mata pencaharian pesisir dan kebutuhan sosial, dan 6. Polusi. Sejalan dengan kebutuhan untuk perencanaan terpadu, tumpang tindih dan trade-off antara rekomendasi sektoral diidentifikasi, dan dalam kerangka teoritis tata kelola adaptif, serta evolusi dan antisipatif, serangkaian saran umum untuk pendekatan tata kelola inklusif terintegrasi ditampilkan dalam bab ini.

The main effects of El Nino and La Nina on fish are increases in mortality rates, abundance and recruitment variation, and expansion/restriction in the range of distribution and spawning areas. Potentially, the interactions with seasonal effects can further exacerbate or dampen fluctuations in these parameters. The objective of this work, therefore, was to characterize the possible differences in the reef fish community structure in two seasons of the year (warm/cold) and between years (2010/2012) following El Nino-La Nina events. There were no significant differences in mean species richness between years. Furthermore, although more than twice the number of individuals was observed in the year after La Nina (2012) compared to the year following El Nino (2010), there were no significant differences with respect to mean abundance per transect. The total number of species recorded was slightly higher in the cold season, with 68 species across both years. In contrast, the total abundance was higher in the warm season. However, differences between seasons were neither significant for mean species richness nor for mean abundance. Neither season nor year exhibited a significant effect on community composition. The cold season in the Gulf of California is characterized by intense winds which generate a greater mixed layer; this, in turn, increases productivity, with cascading effects on higher trophic levels. In contrast, the presence of nitrogen-fixing picocyanobacteria which increase the levels of primary production may be a factor leading to maintaining a similar fish abundance in the warm season. Fluctuations between seasons and years of study were observed for some individual species, which may be related to oceanic productivity and reproductive periods. The results obtained in this work indicate that seasonality and climatic phenomena such El Nino and La Nina do not have a marked effect on community attributes of rocky reef fish in the southern Gulf of California, which apparently form a seasonally stable community, despite some fluctuations in individual species.

Epilithic algae are a ubiquitous component of coral reefs. Components of the epilithic algal matrix (EAM) can have a significant influence on coral settlement and benthic feeding by fishes. We employed a herbivore exclusion experiment on a fringing reef in Viti Levu, Fiji, to investigate the functional role of herbivorous fishes in affecting the EAM between different habitat types and levels of community-based fishing restriction. We surveyed the herbivorous fish community and deployed experimental tiles on the reef flat and lagoonal slope and inside and outside of an area where fishing is restricted (tabu). Tiles were deployed for 3 months, half within cages to exclude herbivorous fishes. We then identified algal type and quantified epilithic algal turf height, sediment dry weight, and detritus within the EAM on each tile. EAM that developed under herbivory was remarkably similar, regardless of the differences in habitat or fishing restriction. In contrast, EAM within cages was characterised by longer turf, heavier sediment load, and high variance in turf length and sediment load. Habitat type played a strong role in determining EAM characteristics where herbivores were excluded. Caged EAM on the reef flat was characterised by algal turf and fleshy macroalgae, whereas EAM in cages on the lagoonal slope was overwhelmingly dominated by filamentous and mat-forming cyanobacteria. The results presented here demonstrate the importance of herbivorous fishes in maintaining a benthic environment favourable to coral settlement and survival. Our results suggest that herbivore biomass per se is not a reliable predictor of foraging activity. Moreover, these results show that the absence of herbivore foraging can have different consequences depending on the habitat type, even within the same reef.

In most coastal communities throughout the South Pacific customary rights to regulate access to vital and scarce resources evolved a long time ago. In many places, these systems have formed the basis of community-based marine management efforts. At the same time, national (fisheries and environmental) legislation regulates various aspects regarding the marine realm. The result is a legal pluralist situation – a circumstance that can affect the governability of coastal fisheries. This study draws on data from Fiji and Solomon Islands to examine how the national marine governance frameworks and customary/community-based marine resource management interact. Fiji has a centralized government and customary governance structures are fairly well defined. Various mechanisms exist that link the national and customary systems. In Solomon Islands customary systems and national governance authority are more dispersed and the latter is partly delegated to provincial governments. Here, partner organizations that engage in local marine management can play a vital role in bridging local and (sub-) national levels. The analysis of the two countries reveals that legal pluralist patterns can play out and be addressed differently. A deeper understanding of the interactions between national and customary marine governance systems can help to design procedures or legal mechanisms which optimize relations across levels and systems, and thus contribute to improving governance outcomes.

A complex landscape for reef management Coral reefs are among the most biodiverse systems in the ocean, and they provide both food and ecological services. They are also highly threatened by climate change and human pressure. Cinner et al. looked at how best to maximize three key components of reef use and health: fish biomass, parrotfish grazing, and fish trait diversity. They found that when human pressure is low, all three traits can be maximized at high conservation levels. However, as human use and pressure increase, it becomes increasingly difficult to promote biodiversity conservation. At some levels of human impact, even the highest amount of protection is not able to maximize biodiversity conservation. Science , this issue p. 307

Coral reef ecosystems have suffered an unprecedented loss of habitat-forming hard corals in recent decades. While marine conservation has historically focused on passive habitat protection, demand for and interest in active restoration has been growing in recent decades. However, a disconnect between coral restoration practitioners, coral reef managers and scientists has resulted in a disjointed field where it is difficult to gain an overview of existing knowledge. To address this, we aimed to synthesise the available knowledge in a comprehensive global review of coral restoration methods, incorporating data from the peer-reviewed scientific literature, complemented with grey literature and through a survey of coral restoration practitioners. We found that coral restoration case studies are dominated by short-term projects, with 60% of all projects reporting less than 18 months of monitoring of the restored sites. Similarly, most projects are relatively small in spatial scale, with a median size of restored area of 100 m2. A diverse range of species are represented in the dataset, with 229 different species from 72 coral genera. Overall, coral restoration projects focused primarily on fast-growing branching corals (59% of studies), and report survival between 60 and 70%. To date, the relatively young field of coral restoration has been plagued by similar ‘growing pains’ as ecological restoration in other ecosystems. These include 1) a lack of clear and achievable objectives, 2) a lack of appropriate and standardised monitoring and reporting and, 3) poorly designed projects in relation to stated objectives. Mitigating these will be crucial to successfully scale up projects, and to retain public trust in restoration as a tool for resilience based management. Finally, while it is clear that practitioners have developed effective methods to successfully grow corals at small scales, it is critical not to view restoration as a replacement for meaningful action on climate change.

Ecological regime shifts in the marine realm have been recorded from a variety of systems and locations around the world. Coral reefs have been especially affected, with their benthic habitat changing from a dominance of stony corals to a dominance of other organisms such as fleshy algae. To detect changes in the benthic habitat of coral reefs, simple tools applicable on a global scale are necessary for future monitoring programs. Hence, the aim of this research is to explore the hypothesis that shifts in assemblages of large benthic foraminifera (LBF) can detect early signs of degradation in the reef benthic habitat. To do so, data on living assemblages of LBF collected between 1997 and 2018 at 12 islands in the Spermonde Archipelago (South Sulawesi, Indonesia) were analyzed. Foraminiferal specimens were morphologically identified to the species level and statistical analyses performed to assess changes in their assemblage composition. A clear temporal shift was observed. Typical foraminiferal assemblages in a coral-dominated (e.g., Amphistegina lobifera, Calcarina spengleri, Heterostegina depressa) and fleshy algae-dominated (e.g., Neorotalia gaimardi, C. mayori) reef habitats were identified and significantly linked to the substrate type. Other species (e.g., Elphidium spp., Peneroplis planatus and Sphaerogypsina globulus) seem to reflect a spatial and temporal gradient of anthropogenic pollution from local inhabited islands and ongoing urban development on the mainland. Hence communities of LBF consistently follow gradual shifts in environmental conditions. Additionally to foraminiferal assemblages being an indicator for actual reef condition, closely monitoring LBF may provide early information on reef degradation, in time to take action against identified stressors (e.g., eutrophication or intensive fishing) at local and regional scales. The circumtropical distribution of LBF is such that they can be included worldwide in reef monitoring programs, conditional to calibration to the regional species pool.

SUMMARYBecause the Anthropocene by definition is an epoch during which environmental change is largely anthropogenic and driven by social, economic, psychological and political forces, environmental social scientists can effectively analyse human behaviour and knowledge systems in this context. In this subject review, we summarize key ways in which the environmental social sciences can better inform fisheries management policy and practice and marine conservation in the Anthropocene. We argue that environmental social scientists are particularly well positioned to synergize research to fill the gaps between: (1) local behaviours/needs/worldviews and marine resource management and biological conservation concerns; and (2) large-scale drivers of planetary environmental change (globalization, affluence, technological change, etc.) and local cognitive, socioeconomic, cultural and historical processes that shape human behaviour in the marine environment. To illustrate this, we synthesize the roles of various environmental social science disciplines in better understanding the interaction between humans and tropical marine ecosystems in developing nations where issues arising from human–coastal interactions are particularly pronounced. We focus on: (1) the application of the environmental social sciences in marine resource management and conservation; (2) the development of ‘new’ socially equitable marine conservation; (3) repopulating the seascape; (4) incorporating multi-scale dynamics of marine social–ecological systems; and (5) envisioning the future of marine resource management and conservation for producing policies and projects for comprehensive and successful resource management and conservation in the Anthropocene.

Coral reefs are amongst the most diverse ecosystems on Earth where complex inter-specific interactions are ubiquitous. An example of such interactions is the mutualistic relationship between damselfishes and branching corals in the Northern Red Sea, where the fish use corals as shelter and provide them with nutrients, enhance the flow between their branches, and protect them from predators. By enhancing the flow between the coral branches, the fish ventilate the coral's inner zone, mitigating hypoxic conditions that otherwise develop within that zone during the night. Here, we tested, for the first time, the effects of the damselfish Dascyllus marginatus on photosynthesis and respiration in its host coral Stylophora pistillata. Laboratory experiments using an intermittent-flow respirometer showed that the presence of fish between the coral branches under light conditions augmented the coral's photosynthetic rate. No effect on the coral's respiration was found under dark conditions. When a fish was allowed to enter the inner zone of a dead coral skeleton, its respiration was higher than when it was in a live coral. Field observations indicated that damselfish were present between coral branches 18–34% of the time during daylight hours and at all times during the night. Considering the changes induced by the fish together with the proportion of time they were found between coral branches in the field, the effect of the fish amounted to an augmentation of 3–6% of the coral's daily photosynthesis. Our findings reveal a previously unknown positive contribution of coral-dwelling fish to their host's photosynthesis.

In reefs, fish distribution and community structure are strongly linked to habitat structure. The objective of this study was to develop a baseline of the attributes of a rocky reef fish community threatened by development and their possible relationship with habitat complexity in order to assess how predicted habitat modification would impact the fish community. In the study area, the construction of a tourist marina is planned as part of a residential area with a total size of 500 ha. The project includes the translocation of corals, infilling of reclamation areas by dredging, and floating docks, which is predicted to affect both benthic rugosity and the types of benthic cover. Using hierarchical clustering based on benthic substrate type and rugosity we defined three levels of habitat complexity (Low, Medium, High). The fish community at different levels of complexity was characterized in terms of species richness, abundance, diversity and dominance, and was classified into seven trophic groups. Transects with high habitat complexity featured the highest cover of dead coral with macroalgae (43.7% ± 2.3, mean ± SE) and live coral (21.0% ± 1.9). There were no significant differences in rugosity among the three levels of habitat complexity (ANOVA, F = 0.145, df = 2, p = 0.87). A total of 19,799 individuals belonging to 76 species were recorded over an area of 12,000 m 2 . The greatest mean density and species richness occurred at high habitat complexity, with 1229.7 (±202.7) individuals per 500 m 2 and 64 species, respectively. Community structure was significantly different in richness and abundance between high and low levels of complexity ( p

Securing ecosystem functions is challenging, yet common priority in conservation efforts. While marine parks aim to meet this challenge by regulating fishing through zoning plans, their effectiveness hinges on compliance levels and may respond to changes in fishing practices. Here we use a speciose assemblage of nominally herbivorous reef fish in Karimunjawa National Park (zoned since 1989) to investigate whether areas subject to a restrictive management regime sustained higher biomass over seven years compared to areas where moderate and permissive regulations apply. Using a trait-based approach we characterize the functional space of the entire species pool and ask whether changes in biomass translate into changes in functional structure. We track changes in predator biomass, benthic community structure, and fishing practices that could influence herbivore trajectories. Overall herbivore biomass doubled in 2012 compared to 2006-2009 and remained high in 2013 across all management regimes. We found no evidence that this biomass build-up resulted from predator depletion or increased food availability but suggest it emerged in response to a park-wide cessation of fishing with large drive nets known as muroami. The biomass increase was accompanied by a modest increase in taxonomic richness and a slight decrease in community-scale rarity that did not alter functional redundancy levels. Subtle changes in both functional specialization and identity of assemblages emerged as generalist species with low intrinsic vulnerability to fishing recovered sooner than more vulnerable specialists. While this implies a recovery of mechanisms responsible for the grazing of algal turfs and detritus, restoring other facets of herbivory (e.g., macroalgal consumption) may require more time. An increase in the cost-benefit ratio per journey of muroami fishing facilitated a ban on muroami nets that met minimal resistance. Similar windows of opportunity may emerge elsewhere in which gear-based regulations can supplement zoning plans, especially when compliance is low. This does not advocate for implementing such regulations once a fishery has become unprofitable. Rather, it underlines their importance for breaking the cycle of resource depletion and low compliance to zoning, thus alleviating the resulting threats to food security and ecosystem integrity.

Java is the economic and political center of Indonesia, a country with > 17,500 islands. Southeast Asia is a hotspot of marine biodiversity, and Java hosts coral reefs, seagrass beds, and mangrove forests, which have an unparalleled role in providing ecosystem services. The Indonesian seas play a decisive role for the coupled ocean and climate system. For the local population, coastal and marine resources are a crucial protein source and have a high economic importance. Java is one of the most densely populated regions in the world, so there is a very strong influence of human activities on the terrestrial and marine ecosystems. Overexploitation, pollution, and ecosystem conversion have already led to habitat degradation and shortage of many natural resources. Here we review the regional oceanic system of Java, its major coastal habitats, coastal and marine resource uses, and human impacts on its coastal and marine ecosystems.

Competition between corals and macroalgae is frequently observed on reefs with the outcome of these interactions affecting the relative abundance of reef organisms and therefore reef health. Anthropogenic activities have resulted in increased atmospheric CO2 levels and a subsequent rise in ocean temperatures. In addition to increasing water temperature, elevated CO2 levels are leading to a decrease in oceanic pH (ocean acidification). These two changes have the potential to alter ecological processes within the oceans, including the outcome of competitive coral-macroalgal interactions. In our study, we explored the combined effect of temperature increase and ocean acidification on the competition between the coral Porites lobata and on the Great Barrier Reef abundant macroalga Chlorodesmis fastigiata. A temperature increase of +1 °C above present temperatures and CO2 increase of +85 ppm were used to simulate a low end emission scenario for the mid- to late 21st century, according to the Representative Concentration Pathway 2.6 (RCP2.6). Our results revealed that the net photosynthesis of P. lobata decreased when it was in contact with C. fastigiata under ambient conditions, and that dark respiration increased under RCP2.6 conditions. The Photosynthesis to Respiration (P:R) ratios of corals as they interacted with macroalgal competitors were not significantly different between scenarios. Dark calcification rates of corals under RCP2.6 conditions, however, were negative and significantly decreased compared to ambient conditions. Light calcification rates were negatively affected by the interaction of macroalgal contact in the RCP2.6 scenario, compared to algal mimics and to coral under ambient conditions. Chlorophyll a, and protein content increased in the RCP2.6 scenario, but were not influenced by contact with the macroalga. We conclude that the coral host was negatively affected by RCP2.6 conditions, whereas the productivity of its symbionts (zooxanthellae) was enhanced. While a negative effect of the macroalga (C. fastigiata) on the coral (P. lobata) was observed for the P:R ratio under control conditions, it was not enhanced under RCP2.6 conditions.

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.

The global accelerating loss of biodiversity is having immediate repercussions for ecosystems and human wellbeing, particularly in areas where people depend intimately on their natural environment for their livelihoods. Dovetailing this loss is the demise of local/traditional knowledge systems resulting from factors such as changing lifestyle and the transformation of local belief systems. While the importance of local ecological knowledge (LEK) for documentation of biodiversity and environmental change and development of management responses is well established, quantitative tools to analyze and systematically compare LEK are scarce. In this research, we analyze the complexity of local ecological knowledge used by respondents to classify locally-recognized marine species. We do so by applying a modified index of taxonomic distinctness to an ethnoichthyological classification in coastal communities in the Solomon Islands. In addition, we assess simple taxonomic diversity (richness in locally-recognized species names) by comparing taxonomies collected in 1992–1995 and 2014–2015. Results indicate that both endogenous (gender, age) and exogenous (proximity to market) factors have discernible effects on folk taxonomic knowledge in the region, with younger respondents and communities closer to a regional market center displaying a significantly lower richness of local species names. Folk taxonomic distinctness was significantly reduced closer to the regional market. The modified index of taxonomic distinctness applied in this research provides a useful tool to explore facets of local ecological knowledge in addition to simple richness of terms, and to compare across different regions and cultural backgrounds. Understanding changes in LEK is important because such knowledge enables communities who are highly dependent on living natural resources to harvest and manage resources more efficiently and also to detect and react to environmental change.

Coral reefs are subject to multiple stressors. Global stressors include climate change and ocean acidification, while local stressors include overfishing and eutrophication. Some stressors stem from land-based activities, like intensive agriculture or sewage production, while others are sea-based, like fishing or diving. Processes that aim to tackle coral degradation are transpiring on different levels. These include the UNDP's Sustainable Development Goal 14, and the Coral Triangle Initiative, which foresees the installation of marine protected areas and conservation planning. This paper uses Evolutionary Governance Theory (EGT) to understand the current processes of changes in governance influencing coral reef health. EGT sees the change of governance as an evolutionary process. It emphasises that discourses play a crucial role in understanding governance evolution. Power, in particular power-knowledge in the Foucaultian sense, plays a crucial role as a driving factor. Governance does not change in a vacuum, but according to EGT is shaped by path, inter- and goal dependencies. Of late, the role of materiality - ecological and technological conditions - has been stressed as an important driver of governance change. The paper considers the main threats to corals identified in the literature and analyses how those factors mentioned by EGT help us to understand the observed governance changes. The case of coral reefs was chosen as it represents an example of extremely diverse processes of institutional changes. Therefore, it is well suited to learn if EGT helps in understanding governance changes observed in the marine sector.

Determining whether many functionally complementary species or only a subset of key species are necessary to maintain ecosystem functioning and services is a critical question in community ecology and biodiversity conservation. Identifying such key species remains challenging, especially in the tropics where many species co-occur and can potentially support the same or different processes. Here, we developed a new community-wide scan (CWS) approach, analogous to the genome-wide scan, to identify fish species that significantly contribute, beyond the socio-environmental and species richness effects, to the biomass and coral cover on Indo-Pacific reefs. We found that only a limited set of species (51 out of approx. 400, approx. 13%), belonging to various functional groups and evolutionary lineages, are strongly and positively associated with fish biomass and live coral cover. Many of these species have not previously been identified as functionally important, and thus may be involved in unknown, yet important, biological mechanisms that help sustain healthy and productive coral reefs. CWS has the potential to reveal species that are key to ecosystem functioning and services and to guide management strategies as well as new experiments to decipher underlying causal ecological processes. © 2018 The Author(s).

Observations of coral–algal competition can provide valuable information about the state of coral reef ecosystems. Here, we report contact rates and apparent competition states for six shallow lagoonal reefs in Fiji. A total of 81.4% of examined coral perimeters were found to be in contact with algae, with turf algae (54.7%) and macroalgae of the genus Lobophora (16.8%) representing the most frequently observed contacts. Turf algae competitiveness was low, with 21.8% of coral–turf contacts being won by the algae (i.e. overgrowth or bleaching of coral tissue). In contrast, Lobophora competitiveness against corals was high, with 62.5% of contacts being won by the alga. The presence of epiphytic algae on Lobophora was associated with significantly greater algal competitiveness against corals, with 75.8% and 21.1% of interactions recorded as algal wins in the presence and absence of epiphytes, respectively. Sedimentation rate, herbivorous fish biomass, and coral colony size did not have a significant effect on Lobophora–coral interactions. This research indicates a novel and important role of epiphytes in driving the outcome of coral–algal contacts.

International audience; Predation is a key ecosystem function, especially in high diversity systems such as coral reefs. Not only is predation one of the strongest top-down controls of prey population density, but it also is a strong driver of prey behaviour and function through non-lethal effects. We ask whether predation risk influences sheltering behaviour of damselfish living in mutualism with branching corals. Host corals gain multiple advantages from the mutualistic relationship which are determined by the strength of damselfish sheltering. Distance travelled by the Lemon Damselfish Pomacentrus moluccensis away from their host colony was measured here as a proxy for sheltering strength and was expected to be shortest under highest predation risk. Predation risk, defined as a function of predator abundance and activity, turbidity and habitat complexity, was quantified at four reef slope sites in Kepulauan Seribu, Indonesia. Damselfish sheltering strength was measured using stationary unmanned video cameras. Small damselfish (< 2 cm) increased their sheltering strength under high turbidity. Predator feeding activity, but not abundance, influenced damselfish sheltering strength. Contrary to our expectations, sheltering behaviour of adult damselfish decreased under high predator activity. While these observations are in line with risk-averse behaviour by juvenile P. moluccensis, they may indicate the presence of sentinel behaviour in the adults of this species. Habitat complexity seemed to be less important as a driver of damselfish behaviour. These counterintuitive results may indicate complex social behaviour and age-specific strategies for predator avoidance.

With increasing stressors to coral reefs, defining tools that evaluate their dynamics and resilience is important to interpret system trajectories and direct conservation efforts. In this context, surveys must go beyond conventional monitoring approaches that focus on abundance and biomass of key groups and quantify metrics that better assess ecological processes and ecosystem trajectories. By measuring a variety of conventional (e.g. proportional cover of broad benthic groups, biomass of herbivorous fish) and complementary resilience-based metrics (e.g. algal turf height, coral recruitment rates, juvenile coral densities, herbivorous fish grazing rates), this study evaluated the ecosystem responses to community-based management in Fiji. The study was conducted across three paired tabu areas (periodically closed to fishing) and adjacent fished sites. Conventional metrics reflected no management effect on benthic or herbivorous fish assemblages. In contrast, the complementary metrics generally indicated positive effects of management, particularly within the benthos. Significant differences were observed for turf height (33% lower), coral recruitment rate (159% higher) and juvenile coral density (42% higher) within areas closed to fishing compared to adjacent open reefs. In addition, turf height was inversely related to coral recruitment and juvenile coral density, and longer turfs (≥5 mm) were more competitive in interaction with corals. These results emphasise that conventional metrics may overlook benefits of local management to inshore reefs, and that incorporating complementary resilience-based metrics such as turf height into reef survey protocols will strengthen their capacity to predict the plausible future condition of reefs and their responses to disturbances., This work was supported by the (German) Federal Ministry of Education and Research (BMBF) through the ‘Nachwuchsgruppen Globaler Wandel 4 + 1’ (REPICORE, grant number 01LN1303A).

International audience; Coral reefs provide ecosystem goods and services for millions of people in the tropics, but reef conditions are declining worldwide. Effective solutions to the crisis facing coral reefs depend in part on understanding the context under which different types of conservation benefits can be maximized. Our global analysis of nearly 1,800 tropical reefs reveals how the intensity of human impacts in the surrounding seascape, measured as a function of human population size and accessibility to reefs ("gravity"), diminishes the effectiveness of marine reserves at sustaining reef fish biomass and the presence of top predators, even where compliance with reserve rules is high. Critically, fish biomass in high-compliance marine reserves located where human impacts were intensive tended to be less than a quarter that of reserves where human impacts were low. Similarly, the probability of encountering top predators on reefs with high human impacts was close to zero, even in high-compliance marine reserves. However, we find that the relative difference between openly fished sites and reserves (what we refer to as conservation gains) are highest for fish biomass (excluding predators) where human impacts are moderate and for top predators where human impacts are low. Our results illustrate critical ecological trade-offs in meeting key conservation objectives: reserves placed where there are moderate-to-high human impacts can provide substantial conservation gains for fish biomass, yet they are unlikely to support key ecosystem functions like higher-order predation, which is more prevalent in reserve locations with low human impacts. marine reserves | fisheries | coral reefs | social-ecological | socioeconomic T he world's coral reefs are rapidly degrading (1-3), which is diminishing ecological functioning and potentially affecting the well-being of the millions of people with reef-dependent livelihoods (4). Global climate change and local human impacts (such as fishing) are pervasive drivers of reef degradation (1, 5). In Significance Marine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass.

Women play an important role within small-scale fishing communities in the South Pacific, contributing to food security and income. Yet, decisions on the management of coastal fisheries are mostly taken by male community leaders. Given that women and men interact with marine spaces differently, there is a need to further analyze women’s and men’s differentiated roles and participation in marine resource use and governance. This study does so by drawing on qualitative data from a case study in Solomon Islands. In the fishing community studied here, women had crucial and differentiated effects on social, economic, and ecological sustainability. Our study reveals that women provided significant social and economic benefits to their families and the broader community. At the same time, we find that some women were inclined towards breaking local marine management rules (i.e., potentially lowering positive ecological effects of the conservation efforts) because (1) women had been little involved in the decision-making with regard to local marine management; (2) women had partly lost trust in the local male leadership due to a perceived misuse of money; and (3) women were more constrained in their fishing activities because a marine closure was located where mainly women used to fish. Our study highlights the importance of paying attention to women’s needs and actions in the governance of the fishery—including both the positive as well as potentially negative consequences thereof. Furthermore, our study shows that, besides gender, other socio-cultural variables (i.e., religious denomination and place of birth) shaped a person’s role and interactions in the fishery. It thus adds weight to intersectional approaches to gender.

Browsing fishes have been identified as an important component of coral reef resilience, because in contrast to other herbivorous fishes they are able to feed on established macroalgae. Climate change and local anthropogenic impacts have contributed to phase shifts in many coral reefs from coral to macroalgae dominance, and recent research suggests the potential ability of browsers to reverse such phase shifts. However, there is high variation among studies and some contradicting findings exist. Here, we review the relevant literature to assemble a list of species currently known to contribute to browsing in the Indo-Pacific. Furthermore, we identify spatial and temporal patterns, outline factors influencing browsing, and discuss the probability of phase shift reversal. We formulate research recommendations addressing the identified gaps in knowledge about the interactions of browsing fishes and their environment. To date, 37 species of fishes have been observed consuming macroalgae in the Indo-Pacific. The most important groups are the family Siganidae, the subfamily Scarinae (Labridae), and the subfamily Nasinae (Acanthuridae). Browsing species vary between studies depending on location, season and macroalgae species examined. Several influencing factors, such as structural complexity, palatability of macroalgae and ecosystem connectivity have been suggested to cause these discrepancies. The most promising avenues for future research are the effect of structural complexity, the importance of mobile link species and influences of food availability on the selectivity of browsing species. Increasing our knowledge in these fields will provide a better basis for successful management strategies directed at increasing the resilience of coral reefs.

This paper arises from a four-year Indonesian-German research cooperation on the governance and management of Indonesian coastal and marine ecosystems. Project objectives were to investigate coastal and marine social-ecological dynamics and feedbacks and to analyse socio-political and institutional structures and processes in order to support adaptive coastal governance. Participating researchers worked in the Spermonde Archipelago, off South Sulawesi, Indonesia, between 2007 and 2010. Methods included ship-based research excursions, several classical surveys, anthropological participant observation, and participatory research methods applied by an interdisciplinary social-natural science team. This paper summarises our findings and draws policy conclusions. First, we discuss Marine Protected Areas and participation focussing on local “rules-in-use”. In addition, reef exploitation and local livelihoods, in particular fisheries and mariculture, and the existing social networks and hierarchies in fisheries are explored to understand social vulnerability, resilience and marine resource governance in the context of the Spermonde Archipelago. An outline of major policy recommendations concludes this article.

A recent review of crown-of-thorns starfish (Acanthaster planci; COTS) in Indonesia has suggested that their impacts have gone under-reported. In 2012–2013, we surveyed COTS at permanent transects within 12 sites of the Spermonde Archipelago, Indonesia, a coastal region close to two rivers and the heavily urbanised city of Makassar. Evidence of COTS was apparent at 8 of 12 sites surveyed with highest densities (37 starfish per 250 m−2 at Barrang Lompo) comparable to those reported in the Indonesian historical literature. At Barrang Lompo and Bonetambung, the COTS outbreak resulted in the loss of half the live coral. Terrestrial effluents have reduced water quality in the Spermonde Archipelago, which further supports recent work linking water quality and COTS outbreaks, thus providing a warning of future outbreaks to Indonesian coastal managers given the country’s increased urbanisation.