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Ocean warming is increasing the incidence, scale, and severity of global-scale coral bleaching and mortality, culminating in the third global coral bleaching event that occurred during record marine heatwaves of 2014-2017. While local effects of these events have been widely reported, the global implications remain unknown. Analysis of 15,066 reef surveys during 2014-2017 revealed that 80% of surveyed reefs experienced significant coral bleaching and 35% experienced significant coral mortality. The global extent of significant coral bleaching and mortality was assessed by extrapolating results from reef surveys using comprehensive remote-sensing data of regional heat stress. This model predicted that 51% of the world’s coral reefs suffered significant bleaching and 15% significant mortality, surpassing damage from any prior global bleaching event. These observations demonstrate that global warming’s widespread damage to coral reefs is accelerating and underscores the threat anthropogenic climate change poses for the irreversible transformation of these essential ecosystems.

Este artículo contiene 17 páginas, 8 figuras, 5 tablas., Complex histories of chronic and acute sea surface temperature (SST) stresses are expected to trigger taxon- and location-specific responses that will ultimately lead to novel coral communities. The 2016 El Niño-Southern Oscillation provided an opportunity to examine largescale and recent environmental histories on emerging patterns in 226 coral communities distributed across 12 countries from East Africa to Fiji. Six main coral communities were identified that largely varied across a gradient of Acropora to massive Porites dominance. Bleaching intensity was taxon-specific and was associated with complex interactions among the 20 environmental variables that we examined. Coral community structure was better aligned with the historical temperature patterns between 1985 and 2015 than the 2016 extreme temperature event. Additionally, bleaching responses observed during 2016 differed from historical reports during past warm years. Consequently, coral communities present in 2016 are likely to have been reorganized by both long-term community change and acclimation mechanisms. For example, less disturbed sites with cooler baseline temperatures, higher mean historical SST background variability, and infrequent extreme warm temperature stresses were associated with Acropora-dominated communities, while more disturbed sites with lower historical SST background variability and frequent acute warm stress were dominated by stress-resistant massive Porites corals. Overall, the combination of taxon-specific responses, community-level reorganization over time, geographic variation, and multiple environmental stressors suggest complex responses and a diversity of future coral communities that can help contextualize management priorities and activities., T.R.M. and N.A.M. received support from the John D. and Catherine T. MacArthur Foundation, and the Sustainable Poverty Alleviation from Coastal Ecosystem Services (SPACES) project, number NE-K010484-1. E.S.D. was supported by an NSERC Banting Postdoctoral Fellowship and the John D. and Catherine T. MacArthur Foundation. Data collection in the Solomon Islands was supported by the Wallace Research Foundation, and the Waitt Foundation supported data collection in Fiji. Maldives data collection was supported by IUCN and USAID. M.M.M.G. received support from the French National Research Agency under the STORISK project (no. ANR-15-CE03- 0003). Data collection in Zanzibar was partly supported by the NORHED project coordinated by the State University of Zanzibar (SUZA). The Tiffany & Co. Foundation and the John D. and Catherine T. MacArthur Foundation supported data collection at sites in the western Indian Ocean. V.J.P. received support from the DST-INSPIRE Faculty Programme, and Z. Tyabji and S. Chandrasekhar assisted V.J.P. with data collection in the Andaman Islands. R.A. received funding support from the Pew Marine Fellowship and an Intramural Project from the Spanish National Research Council (CSIC-201330E062). S.A.K. was funded by the VILLUM Foundation (grant no. 10114). A.T.H. received funding from the Carnegie Corporation of New York. Indonesia data collection was supported by John D. and Catherine T. MacArthur Foundation and Margaret A. Cargill Philanthropies. The following people assisted with data collection: A. Baird, A. Halford, S. Keith, C. Miternique, E. Montocchio, C. Muhando, J. Ndagala, and N. Summers.

Documenting phenologic events is crucial in obtaining deeper insights into the life cycle of seagrasses. We documented and compared the flowering and fruiting of the seagrass Enhalus acoroides from multispecies seagrass meadows at two sites, Henry Lawrence and Tarmugli islands located inside the marine national parks in South Andaman Islands. At these two locations, the average density of shoots ranged between 30.9/m2 and 18.16/m2, fruits between 5/m2 and 2.33/m2, and flowers between 6.7/m2 and 3.83/m2, whereas the mean length of the peduncles ranged from 40.59cm at Henry Lawrence to 32.44cm at Tarmugli Island. We observed significant differences between the densities of shoots and fruits and peduncle lengths in the two sites. The density of flowers, however, did not vary significantly. These observations of fruiting and flowering in E. acoroides establish an important reproductive stage in the life cycle of the species and open avenues for further seagrass research in the Andaman Islands. We describe the findings and emphasize on the need to establish a long-term phenology monitoring program for E. acoroides in the Andaman Archipelago.

The Vulnerable bumphead parrotfish Bolbometopon muricatum, a highly prized fishery resource worldwide, has experienced population declines throughout its geographical range. There is limited knowledge of the distribution and abundance of, and threats to, this fish in Indian waters, particularly for the Andaman and Nicobar Islands. To assess the species’ distribution and conservation status we conducted underwater surveys across 75 sites around 51 islands and interviewed 99 fishers across the Andaman and Nicobar archipelago. We recorded a total of 59 individual B. muricatum across nine sites from the northernmost island in the Andamans (Landfall Island) to the southernmost island in the Nicobars (Great Nicobar Island). Interviews revealed that most fishers (100% in Nicobar, 94% in Middle Andaman, 62% in South Andaman) had seen B. muricatum, and knowledge of the species is highest amongst spearfishers. Generalized linear models indicated that presence of marine protected areas and high live coral cover influenced the abundance and distribution of B. muricatum. The species' density seems to be naturally low in the archipelago. We discuss our findings in the light of protecting rare and threatened species, and recommend strengthening the existing marine protected areas in these islands.

The scientific literature on the diversity and biological characteristics of sharks and rays from the Andaman and Nicobar Archipelago fishing grounds is scarce and compromised by species misidentifications. We carried out systematic fish landing surveys in South Andamans from January 2017 to May 2018, a comprehensive and cost-effective way to fill this data gap. We sampled 5,742 individuals representing 57 shark and ray species. Of the 36 species of sharks and 21 species of rays landed, six species of sharks - Loxodon macrorhinus, Carcharhinus amblyrhynchos, Sphyrna lewini, Carcharhinus albimarginatus, Carcharhinus brevipinna, and Paragaelus randalli dominated landings and comprised 83.35 % of shark landings, while three species of rays were most abundant – Pateobatis jenkinsii, Himantura leoparda and H. tutul, and comprised 48.82 % of ray landings. We report size extensions for seven shark species as well as three previously unreported ray species, increasing the known diversity for the islands and for India. For sharks, mature individuals of small-bodied species (63.48 % males of total landings of species less than 1.5 m total length) and immature individuals of larger species (84.79 % males of total landings of species larger than 1.5 m total length) were mostly landed; whereas for rays, mature individuals were predominantly landed (80.71 % males of total landings) likely reflecting differences in fishing patterns as well as habitat preferences and life history stages across species. Further, juvenile sharks and gravid females were landed in large quantities which might be unsustainable in the long-term. Landings were female-biased in C. amblyrhynchos, S. lewini and P. jenkinsii, and male-biased in L. macrorhinus and H. leoparda, indicating either spatio-temporal or gear specific sexual segregation in these species. Understanding these nuances - the composition and biology of sharks and rays landed in different fisheries seasonally will inform future conservation and fishery management measures for these species in the Andaman and Nicobar Islands.

The Indian Ocean humpback dolphin (Sousa plumbea), a common cetacean species in India, has a diverse vocal repertoire, which to date has not been described in detail. This study focused on analyzing their whistle vocalizations. Humpback dolphins were recorded off the Sindhudurg coast of Maharashtra, India, and 2,260 whistles were analyzed for their acoustic characteristics. Whistles spanned a wide frequency range between 2.3 kHz and 33.0 kHz, with durations ranging from 0.01 s to 1.60 s. Whistles were categorized into seven contour classes based on their qualitative properties. A classification and regression tree (CART) analysis was used to quantify variability between the seven contour classes using the measured acoustic features. Based on the CART analysis, frequency gradient, minimum slope, maximum slope, beginning and ending slope accounted for most variability between whistle types. CART resulted in an overall classification accuracy of 89.5%. This study provides a detailed description of acoustic features and qualitative properties of humpback dolphin whistles from the northwestern coast of India. Further comparisons of acoustic data from Sousa populations along the Indian coast are necessary to determine possible geographic variations in whistle characteristics and whether the variations are driven by environmental or genetic factors or a combination of both.

Two near shore small cetaceans occur commonly along the Maharashtra coast, the Indian Ocean humpback dolphin and Indo Pacific finless porpoise. These cetaceans frequently interact with fisheries in this region due to overlap in space and resource use. Besides stranding records, little ecological information is available about these species from Maharashtra. We conducted 143 semistructured interviews to document local ecological knowledge and community perceptions of small cetaceans in 30 coastal fishing villages in Sindhudurg. Perceptions of finless porpoises were largely neutral, whereas humpback dolphins were negative. A classification regression tree (CART) analysis (root node error: 60%) showed that the annual cost of gear damage was an important predictor variable of humpback dolphin perceptions, followed by occupation (gear type) and age. Entanglements were reported for both species in large and small gill nets, and shore seines. Perceived net damage and catch loss due to humpback dolphins was six times greater than that of finless porpoises. However, finless porpoises were reportedly more frequently entangled in gear than humpback dolphins. We provide an insight into the perceptions of cetaceans in the local community and the fisheries‐cetacean interactions that shape them.

Empirical evidence indicates that for two reef fish groups, chaetodontids and pomacanthids, live coral cover and latitude determine the local abundance and species richness patterns. Most studies have considered the influence of either live coral cover or latitude in isolation, and the interactive effects that are likely to influence the geographical distribution in species richness and diversity has not been explored. In this study we explored the relationship between (1) species richness and latitude, and (2) species richness and benthic variables, (3) species diversity and latitude and (4) species diversity and benthic variables for butterflyfish (Chaetodontidae) and angelfish (Pomacanthidae) at 75 sites across 51 islands in the Andaman and Nicobar (A & N) archipelago. A total of 30 species of chaetodontids belonging to four genera and 13 species of pomacanthids belonging to nine genera were recorded. We found that live coral cover and latitude were the best predictors for explaining variation in the distribution of these fish communities across the A & N archipelago. This is probably because of the high dependence of these two fish groups on live coral cover and Nicobar’s geographical proximity to the Coral Triangle, which is considered to be the center of origin of coral reefs and supports high biodiversity. Our results show that despite the high dependence of chaetodontids and pomacanthids on live coral cover, reduction of live coral cover due to a series of disturbance events had limited influence on species richness of these two fish groups, indicating that broad geographical trends are important in explaining variation in species richness for chaetodontid and pomacanthid fish groups.

Theory, simulations, and experiments are used to study liquid-air interfacial instability of lifted Hele Shaw cells (LHSCs) with a hole in the center. The stability map provides a design framework for using multihole LHSCs to generate stable meshlike patterns in the liquid film.

Este artículo contiene 10 páginas, 5 figuras., Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages—the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014–2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse.

Este artículo contiene 7 páginas, 2 tablas, 2 figuras., Under extreme heat stress, corals expel their symbiotic algae and colour (that is, ‘bleaching’), which often leads to widespread mortality. Predicting the large-scale environmental conditions that reinforce or mitigate coral bleaching remains unresolved and limits strategic conservation actions1,2. Here we assessed coral bleaching at 226 sites and 26 environmental variables that represent different mechanisms of stress responses from East Africa to Fiji through a coordinated effort to evaluate the coral response to the 2014–2016 El Niño/ Southern Oscillation thermal anomaly. We applied common time-series methods to study the temporal patterning of acute thermal stress and evaluated the effectiveness of conventional and new sea surface temperature metrics and mechanisms in predicting bleaching severity. The best models indicated the importance of peak hot temperatures, the duration of cool temperatures and temperature bimodality, which explained ~50% of the variance, compared to the common degree-heating week temperature index that explained only 9%. Our findings suggest that the threshold concept as a mechanism to explain bleaching alone was not as powerful as the multidimensional interactions of stresses, which include the duration and temporal patterning of hot and cold temperature extremes relative to average local conditions., T.R.M. and N.A.M. received support from the John D. and Catherine T. MacArthur Foundation and the Sustainable Poverty Alleviation from Coastal Ecosystem Services (SPACES) NE-K010484-1 project. E.S.D. was supported by a Banting Postdoctoral Fellowship from the Natural Sciences and Engineering Research Council of Canada and the John D. and Catherine T. MacArthur Foundation. Data collection in the Solomon Islands was supported by the Wallace Research Foundation, and the Waitt Foundation supported data collection in Fiji. Maldives data collection was supported by IUCN and USAID. M.M.M.G. received support from the French National Research Agency under the STORISK project (no. ANR-15-CE03-0003). Data collection in Zanzibar was partly supported by the NORHED project coordinated by the State University of Zanzibar (SUZA). The Tiffany & Co. Foundation and the John D. and Catherine T. MacArthur Foundation supported data collection in some Western Indian Ocean reefs. V.J.P. received support from the DST-INSPIRE Faculty Programme, and Z. Tyabji and S. Chandrasekhar assisted V.J.P. with data collection in the Andaman Islands. R.A. received funding support from the Pew Marine Fellowship and an Intramural Project from the Spanish National Research Council (CSIC-201330E062). S.A.K. was funded by the VILLUM Foundation (no. 10114). A.T.H. received funding from the Carnegie Corporation of New York. Indonesia data collection was supported by the John D. and Catherine T. MacArthur Foundation and Margaret A. Cargill Philanthropies. We thank the following people for assistance with data collection: A. Baird, A. Halford, R. J.-L. Komeno, C. Miternique, A. dan Muhidin, E. Muttaqin, E. Montocchio, C. Muhando, S. Pardede, N. Summers and S. Yadav.

Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages-the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014-2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse.

Examining stakeholder's knowledge, perception and attitudes are necessary for effective implementation of laws that are designed to protect and conserve marine biodiversity. In order to understand knowledge, awareness and perception about the law and the species that are protected under the Indian Wildlife (Protection) Act, 1972, I interviewed (N = 159) stakeholders (77 fishermen, 39 authorities and 41 middlemen/traders) in the Andaman Islands, India. Within respondents, mean awareness about different protected marine species was (80%) amongst authorities, followed by (63%) amongst traders/middlemen and (59%) amongst fishermen. The awareness about a few charismatic groups i.e., mammals, reptiles and cnidarians high; whereas awareness about elasmobranchs, fish, sea cucumbers and molluscs low amongst the respondent groups. Amongst several species traded in the islands, the sea cucumber, the trochus and the turbo are in high demand, and there is demand from middlemen and fishers to delist these species. Generalised model revealed that the years of fishing experience, occupation, annual income and age of respondents are important factors in determining awareness of locals towards protected species. Solutions suggested by stakeholders are strict enforcement of the law, education and awareness of protected species, a special task force for dealing with the Indian Wildlife Protection Act, need to curb poaching from foreigners etc. All fishers sell their catch to middlemen/traders who in turn send their catch to mainland India (Tamil Nadu and Kolkata). The knowledge about which government department is responsible for implementation and monitoring of the law is limited amongst all stakeholder groups. The study demonstrates that stakeholder's knowledge, perception and attitude can offer valuable insights towards strengthening the law that protects marine species. Similar studies should be carried out across different coastal states to understand the level of awareness of stakeholders towards protected marine species. Creating awareness, inclusiveness of local stakeholders in decision making, empowering authorities in monitoring can help in strengthening the existing law framework for protected marine species.

We describe the distribution of the coconut crab Birgus latro, categorized as Data Deficient on the IUCN Red List, local perspectives towards the species, and its conservation needs on the Nicobar Islands in the eastern Indian Ocean. The species is threatened with extinction across most of its range and in India it is found only on a few islands in the Andaman and Nicobar archipelagoes. We carried out informal discussions with Nicobari communities to examine issues regarding conservation of the species and conducted timed searches in areas where coconut crabs were likely to be found. The discussions revealed that there are social taboos against hunting the coconut crab on most of the Nicobar Islands. However, on some islands these taboos are not being followed and community members may hunt the crab for consumption. Athough the coconut crab is legally protected under the Indian Wildlife Protection Act none of the villagers were aware of this. Of the six islands surveyed we recorded the presence of 17 and 14 crabs on two islands, respectively. On four islands villagers reported the presence of the crab prior to the tsunami of 2004, and on two of these islands the species may now be locally extinct. A small population size and a fragmented distribution in areas of coconut plantations suggest that the species is threatened. We recommend monitoring and detailed research on the ecology and genetics of the coconut crab, along with community-based conservation initiatives to conserve the species and its habitat.

17 páginas, 5 figuras, 5 tablas, Herds of dugong, a largely tropical marine megaherbivore, are known to undertake long-distance movements, sequentially overgrazing seagrass meadows in their path. Given their drastic declines in many regions, it is unclear whether at lower densities, their grazing is less intense, reducing their need to travel between meadows. We studied the effect of the feeding behaviour of a small dugong population in the Andaman and Nicobar archipelago, India to understand how small isolated populations graze seagrasses. In the seven years of our observation, all recorded dugongs travelled either solitarily or in pairs, and their use of seagrasses was limited to 8 meadows, some of which were persistently grazed. These meadows were relatively large, contiguous and dominated by short-lived seagrasses species. Dugongs consumed approximately 15% of meadow primary production, but there was a large variation (3–40% of total meadow production) in consumption patterns between meadows. The impact of herbivory was relatively high, with shoot densities c. 50% higher inside herbivore exclosures than in areas exposed to repeated grazing. Our results indicate that dugongs in the study area repeatedly graze the same meadows probably because the proportion of primary production consumed reduces shoot density to levels that are still above values that can trigger meadow abandonment. This ability of seagrasses to cope perhaps explains the long-term site fidelity shown by individual dugongs in these meadows. The fact that seagrass meadows in the archipelago are able to support dugong foraging requirements allows us to clearly identify locations where this remnant population persists, and where urgent management efforts can be directed., This work was supported by Ravi Sankaran Inlaks Fellowship Program, to ED; Mohammed Bin Zayed Species Conservation Fund, to ED; Ministry of Environment and Forests, CSIC under the PIE programme (Ref: 201330E062), to TA

11 páginas, 3 tablas, 2 figuras, To sustainably manage naturally scarce resources, island communities often evolve complex mechanisms including customary laws, belief systems, and reciprocity arrangements among others, to prevent overharvest. Their effectiveness depends largely on the extent to which resource users comply with the rules. We examined patterns of compliance with traditional marine management in the Nicobar Archipelago, India, before, and six years after, the 2004 tsunami. We used interview-based surveys to document marine harvest regulations, and changes in compliance patterns. Our results indicate that pre-tsunami, complex harvest rules existed, including spatio-temporal closures, gear restrictions and species bans; many reefs were subject to multiple, overlapping restrictions. Post-tsunami, compliance weakened considerably; younger individuals (19–35 years) and individuals receiving tsunami aid (boats, gear, etc.) were the most likely non-compliers. Around 84 % of interviewees attributed declining compliance directly to post-tsunami changes in resource availability and a perceived decline in traditional authority. Changes in resource availability can interact strongly with institutional decline, eroding the resilience of traditional management.

12 páginas, 5 figuras, 3 tablas, 1 apéndice., Prioritizing efforts for conserving rare and threatened species with limited past data and lacking population estimates is predicated on robust assessments of their occupancy rates. This is particularly challenging for elusive, long-lived and wideranging marine mammals. In this paper we estimate trends in long-term (over 50years) occupancy, persistence and extinction of a vulnerable and data-poor dugong (Dugong dugon) population across multiple seagrass meadows in the Andaman and Nicobar archipelago (India). For this we use hierarchical Bayesian dynamic occupancy models accounting for false negatives (detection probability,1), persistence and extinction, to two datasets: a) fragmentary long-term occurrence records from multiple sources (1959–2004, n = 40 locations), and b) systematic detection/non-detection data from current surveys (2010–2012, n = 57). Dugong occupancy across the archipelago declined by 60% (from 0.45 to 0.18) over the last 20 years and present distribution was largely restricted to sheltered bays and channels with seagrass meadows dominated by Halophila and Halodule sp. Dugongs were not found in patchy meadows with low seagrass cover. In general, seagrass habitat availability was not limiting for dugong occupancy, suggesting that anthropogenic factors such as entanglement in gillnets and direct hunting may have led to local extinction of dugongs from locations where extensive seagrass meadows still thrive. Effective management of these remnant dugong populations will require a multi-pronged approach, involving 1) protection of areas where dugongs still persist, 2) monitoring of seagrass habitats that dugongs could recolonize, 3) reducing gillnet use in areas used by dugongs, and 4) engaging with indigenous/settler communities to reduce impacts of hunting., This research was supported and funded by the Conservation Leadership Program (Future Conservationist Award), Ministry of Environment and Forests (Species Recovery Program), Mohammed Bin Zayed Species Conservation Fund, the Ravi Sankaran Inlaks Small Grants Program and Nature Conservation Foundation (Oceans and Coasts program). TA was partially funded by the project CTM2010-22273-C02 (Plan Nacional I+D+I, Spain). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.