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Healthy marine ecosystems provide critical benefits to people worldwide, but increasing threats from climate change and human activities disrupt ecosystem functionality and put these benefits at risk. Local and regional assessments have shown these impacts can be substantial, but we lack a global assessment of risk to marine biodiversity. Here we assessed risk of impact by intersecting spatial distributions of 21,267 marine animal species with distributions of 13 anthropogenic stressors according to each species’ vulnerability, examining results through multiple lenses that connect to different conservation objectives: species, taxon, and functional vulnerability. Using this species-focused approach, we found that vulnerable functional entities in coastal ecosystems across all marine ecological provinces are at greater risk of impact than indicated by assessments of broader ecosystem-level impact risk based on vulnerability of representative habitats, driven largely by climate stressors. Where multiple lenses of impact assessment indicate elevated risk, broad area-based protections may be warranted, but where impacts are focused on vulnerable functional entities there may be opportunities for more narrowly targeted conservation strategies such as local habitat restoration, assisted migration, or fishing gear restrictions. These results provide key insights at local to global scales on where and how to best meet conservation of species diversity and ecosystem function.

Driven by climate change, marine biodiversity is undergoing a phase of rapid change that has proven to be even faster than changes observed in terrestrial ecosystems. Understanding how these changes in species composition will affect future marine life is crucial for conservation management, especially due to increasing demands for marine natural resources. Here, we analyse predictions of a multiparameter habitat suitability model covering the global projected ranges of >33,500 marine species from climate model projections under three CO2 emission scenarios (RCP2.6, RCP4.5, RCP8.5) up to the year 2100. Our results show that the core habitat area will decline for many species, resulting in a net loss of 50% of the core habitat area for almost half of all marine species in 2100 under the high-emission scenario RCP8.5. As an additional consequence of the continuing distributional reorganization of marine life, gaps around the equator will appear for 8% (RCP2.6), 24% (RCP4.5), and 88% (RCP8.5) of marine species with cross-equatorial ranges. For many more species, continuous distributional ranges will be disrupted, thus reducing effective population size. In addition, high invasion rates in higher latitudes and polar regions will lead to substantial changes in the ecosystem and food web structure, particularly regarding the introduction of new predators. Overall, our study highlights that the degree of spatial and structural reorganization of marine life with ensued consequences for ecosystem functionality and conservation efforts will critically depend on the realized greenhouse gas emission pathway.

By-catch is the most significant direct threat marine megafauna face at the global scale. However, the magnitude and spatial patterns of megafauna by-catch are still poorly understood, especially in regions with very limited monitoring and expanding fisheries. The Indian Ocean is a globally important region for megafauna biodiversity and for tuna fisheries, but has limited by-catch data. Anecdotal and scattered information indicates high by-catch could be a major threat. Here, we adapt a Productivity Susceptibility Analysis tool designed for data-poor contexts to present the first spatially explicit estimates of by-catch risk of sea turtles, elasmobranchs, and cetaceans in the three major tuna fishing gears (purse seines, longlines, and drift gill nets). Our assessment highlights a potential opportunity for multi-taxa conservation benefits by concentrating management efforts in particular coastal regions. Most coastal waters in the northern Indian Ocean, including countries that have had a minimal engagement with regional management bodies, stand out as high risk for fisheries interactions. In addition to species known to occur in tuna gears, we find high vulnerability to multiple gear types for many poorly known elasmobranchs that do not fall under any existing conservation and management measures. Our results indicate that current by-catch mitigation measures, which focus on safe-release practices, are unlikely to adequately reduce the substantial cumulative fishing impacts on vulnerable species. Preventative solutions that reduce interactions with non-target species (such as closed areas or seasons, or modifications to gear and fishing tactics) are crucial for alleviating risks to megafauna from fisheries.

Climate change is impacting virtually all marine life. Adaptation strategies will require a robust understanding of the risks to species and ecosystems and how those propagate to human societies. We develop a unified and spatially explicit index to comprehensively evaluate the climate risks to marine life. Under high emissions (SSP5-8.5), almost 90% of similar to 25,000 species are at high or critical risk, with species at risk across 85% of their native distributions. One tenth of the ocean contains ecosystems where the aggregated climate risk, endemism and extinction threat of their constituent species are high. Climate change poses the greatest risk for exploited species in low-income countries with a high dependence on fisheries. Mitigating emissions (SSP1-2.6) reduces the risk for virtually all species (98.2%), enhances ecosystem stability and disproportionately benefits food-insecure populations in low-income countries. Our climate risk assessment can help prioritize vulnerable species and ecosystems for climate-adapted marine conservation and fisheries management efforts.

Recreational fisheries contribute substantially to the sociocultural and economic well-being of coastal and riparian regions worldwide, but climate change threatens their sustainability. Fishery managers require information on how climate change will impact key recreational species; however, the absence of a global assessment hinders both directed and widespread conservation efforts. In this study, we present the first global climate change vulnerability assessment of recreationally targeted fish species from marine and freshwater environments (including diadromous fishes). We use climate change projections and data on species' physiological and ecological traits to quantify and map global climate vulnerability and analyze these patterns alongside the indices of socioeconomic value and conservation effort to determine where efforts are sufficient and where they might fall short. We found that over 20% of recreationally targeted fishes are vulnerable to climate change under a high emission scenario. Overall, marine fishes had the highest number of vulnerable species, concentrated in regions with sensitive habitat types (e.g., coral reefs). However, freshwater fishes had higher proportions of species at risk from climate change, with concentrations in northern Europe, Australia, and southern Africa. Mismatches in conservation effort and vulnerability were found within all regions and life-history groups. A key pattern was that current conservation effort focused primarily on marine fishes of high socioeconomic value rather than on the freshwater and diadromous fishes that were predicted to be proportionately more vulnerable. While several marine regions were notably lacking in protection (e.g., Caribbean Sea, Banda Sea), only 19% of vulnerable marine species were without conservation effort. By contrast, 72% of freshwater fishes and 33% of diadromous fishes had no measures in place, despite their high vulnerability and cultural value. The spatial and taxonomic analyses presented here provide guidance for the future conservation and management of recreational fisheries as climate change progresses.

Several Arctic marine mammal species are predicted to be negatively impacted by rapid sea ice loss associated with ongoing ocean warming. However, consequences for Arctic whales remain uncertain. To investigate how Arctic whales responded to past climatic fluctuations, we analysed 206 mitochondrial genomes from beluga whales (Delphinapterus leucas) sampled across their circumpolar range, and four nuclear genomes, covering both the Atlantic and the Pacific Arctic region. We found four well-differentiated mitochondrial lineages, which were established before the onset of the last glacial expansion ~110 thousand years ago. Our findings suggested these lineages diverged in allopatry, reflecting isolation of populations during glacial periods when the Arctic sea-shelf was covered by multiyear sea ice. Subsequent population expansion and secondary contact between the Atlantic and Pacific Oceans shaped the current geographic distribution of lineages, and may have facilitated mitochondrial introgression. Our demographic reconstructions based on both mitochondrial and nuclear genomes showed markedly lower population sizes during the Last Glacial Maximum (LGM) compared to the preceding Eemian and current Holocene interglacial periods. Habitat modelling similarly revealed less suitable habitat during the LGM (glacial) than at present (interglacial). Together, our findings suggested the association between climate, population size, and available habitat in belugas. Forecasts for year 2100 showed that beluga habitat will decrease and shift northwards as oceans continue to warm, putatively leading to population declines in some beluga populations. Finally, we identified vulnerable populations which, if extirpated as a consequence of ocean warming, will lead to a substantial decline of species-wide haplotype diversity.

1. Climate change is already having profound effects on biodiversity, but climate change adaptation has yet to be fully incorporated into area-based management tools used to conserve biodiversity, such as protected areas. One main obstacle to its inclusion is the lack of consensus regarding how impacts of climate change can be included in spatial conservation plans.2. We propose a climate-smart framework that prioritizes the protection of climate refugia—areas of low climate exposure and high biodiversity retention—identified using climate metrics. We explore four aspects of climate-smart spatial planning in the proposed framework: i) climate model ensembles; ii) multiple emission scenarios; iii) climate metrics; and iv) approaches to identifying climate refugia. We illustrate this framework in the Western Pacific Ocean, but it is equally applicable to terrestrial systems.3. All aspects of climate-smart spatial planning considered affected the configuration of spatial plans. The choice of climate metrics and approaches to identifying refugia result in large differences in climate-smart spatial plans, whereas the choice of climate models and emission scenarios have smaller effects. As configuration of spatial plans depended on climate metrics used, a spatial plan based on a single measure of climate change (e.g., warming) will not necessarily be robust against other measures of climate change (e.g., ocean acidification). We recommend including climate metrics most relevant for the biodiversity considered. To include the uncertainty associated with different climate futures, we recommend using multiple climate models (i.e., an ensemble) and emission scenarios. Finally, we show that the approaches we used to identify climate refugia come with trade-offs between the degree to which they are climate-smart and their efficiency in meeting conservation targets. Hence, the choice of approach will depend on the relative value stakeholders place on climate change adaptation.4. By using this framework, protected areas can be designed with improved longevity and thus safeguard biodiversity against current and future climate change. We hope that the proposed climate-smart framework helps transition conservation planning towards climate-smart approaches.

The ocean contains unique biodiversity, provides valuable food resources and is a major sink for anthropogenic carbon. Marine protected areas (MPAs) are an effective tool for restoring ocean biodiversity and ecosystem services1,2, but at present only 2.7% of the ocean is highly protected3. This low level of ocean protection is due largely to conflicts with fisheries and other extractive uses. To address this issue, here we developed a conservation planning framework to prioritize highly protected MPAs in places that would result in multiple benefits today and in the future. We find that a substantial increase in ocean protection could have triple benefits, by protecting biodiversity, boosting the yield of fisheries and securing marine carbon stocks that are at risk from human activities. Our results show that most coastal nations contain priority areas that can contribute substantially to achieving these three objectives of biodiversity protection, food provision and carbon storage. A globally coordinated effort could be nearly twice as efficient as uncoordinated, national-level conservation planning. Our flexible prioritization framework could help to inform both national marine spatial plans4 and global targets for marine conservation, food security and climate action. Using a globally coordinated strategic conservation framework to plan an increase in ocean protection through marine protected areas can yield benefits for biodiversity, food provisioning and carbon storage.

Understanding a species response to past environmental changes can help forecast how they will cope with ongoing climate changes. Harbor porpoises are widely distributed in the North Atlantic and were deeply impacted by the Pleistocene changes with the split of three sub-species. Despite major impacts of fisheries on natural populations, little is known about population connectivity and dispersal, how they reacted to the Pleistocene changes and how they will evolve in the future. Here, we used phylogenetics, population genetics, and predictive habitat modelling to investigate population structure and phylogeographic history of the North Atlantic porpoises. A total of 925 porpoises were characterized at 10 microsatellite loci and one-quarter of the mitogenome (mtDNA). A highly divergent mtDNA lineage was uncovered in one porpoise off Western Greenland, suggesting that a cryptic group may occur and could belong to a recently discovered mesopelagic ecotype off Greenland. Aside from it and the southern sub-species, spatial genetic variation showed that porpoises from both sides of the North Atlantic form a continuous system belonging to the same subspecies (Phocoena phocoena phoceona). Yet, we identified important departures from random mating and restricted intergenerational dispersal forming a highly significant isolation-by-distance (IBD) at both mtDNA and nuclear markers. A ten times stronger IBD at mtDNA compared to nuclear loci supported previous evidence of female philopatry. Together with the lack of spatial trends in genetic diversity, this IBD suggests that migration-drift equilibrium has been reached, erasing any genetic signal of a leading-edge effect that accompanied the predicted recolonization of the northern habitats freed from Pleistocene ice. These results illuminate the processes shaping porpoise population structure and provide a framework for designing conservation strategies and forecasting future population evolution.

Marine protected areas (MPAs) are key to averting continued loss of species and ecosystem services in our oceans, but concerns around economic trade-offs hamper progress. Here we provide optimized planning scenarios for global MPA networks that secure species habitat while minimizing impacts on fisheries revenues. We found that MPA coverage requirements differ vastly among nations, and that two-thirds of nations benefit economically from a collaborative approach. Immediate global protection of marine biodiversity habitat comes with losses of ~19% of total fisheries revenues, but international cooperation in concert with high seas protection improves economic losses for most countries, safeguards all species, and could save ~5B USD annually worldwide. Nations and fishery economies both share benefits from a coordinated approach to conserving marine biodiversity, with direct relevance to current international policies.

One of the aims of the United Nations (UN) negotiations on the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction (ABNJ) is to develop a legal process for the establishment of area-based management tools, including marine protected areas, in ABNJ. Here we use a conservation planning algorithm to integrate 55 global data layers on ABNJ species diversity, habitat heterogeneity, benthic features, productivity, and fishing as a means for highlighting priority regions in ABNJ to be considered for spatial protection. We also include information on forecasted species distributions under climate change. We found that parameterizing the planning algorithm to protect at least 30% of these key ABNJ conservation features, while avoiding areas of high fishing effort, yielded a solution that highlights 52,545,634 km2 (23.7%) of ABNJ as high priority regions for protection. Instructing the planning model to avoid ABNJ areas with high fishing effort resulted in relatively minor shifts in the planning solution, when compared to a separate model that did not consider fishing effort. Integrating information on climate change had a similarly minor influence on the planning solution, suggesting that climate-informed ABNJ protected areas may be able to protect biodiversity now and in the future. This globally standardized, data-driven process for identifying priority ABNJ regions for protection serves as a valuable complement to other expert-driven processes underway to highlight ecologically or biologically significant ABNJ regions. Both the outputs and methods exhibited in this analysis can additively inform UN decision-making concerning establishment of ABNJ protected areas.

Slower warming in the deep ocean encourages a perception that its biodiversity is less exposed to climate change than that of surface waters. We challenge this notion by analysing climate velocity, which provides expectations for species’ range shifts. We find that contemporary (1955–2005) climate velocities are faster in the deep ocean than at the surface. Moreover, projected climate velocities in the future (2050–2100) are faster for all depth layers, except at the surface, under the most aggressive GHG mitigation pathway considered (representative concentration pathway, RCP 2.6). This suggests that while mitigation could limit climate change threats for surface biodiversity, deep-ocean biodiversity faces an unavoidable escalation in climate velocities, most prominently in the mesopelagic (200–1,000 m). To optimize opportunities for climate adaptation among deep-ocean communities, future open-ocean protected areas must be designed to retain species moving at different speeds at different depths under climate change while managing non-climate threats, such as fishing and mining. Marine biodiversity is at risk as the ocean warms, but currently the focus has been at the surface as the deep ocean has warmed less. Climate velocity—the speed and direction of isotherm displacement—is calculated to be faster in the deep ocean, and projections show this difference will grow.

The Arctic is warming at an unprecedented rate, with unknown consequences for endemic fauna. However, Earth has experienced severe climatic oscillations in the past, and understanding how species responded to them might provide insight into their resilience to near-future climatic predictions. Little is known about the responses of Arctic marine mammals to past climatic shifts, but narwhals (Monodon monoceros) are considered one of the endemic Arctic species most vulnerable to environmental change. Here, we analyse 121 complete mitochondrial genomes from narwhals sampled across their range and use them in combination with species distribution models to elucidate the influence of past and ongoing climatic shifts on their population structure and demographic history. We find low levels of genetic diversity and limited geographic structuring of genetic clades. We show that narwhals experienced a long-term low effective population size, which increased after the Last Glacial Maximum, when the amount of suitable habitat expanded. Similar post-glacial habitat release has been a key driver of population size expansion of other polar marine predators. Our analyses indicate that habitat availability has been critical to the success of narwhals, raising concerns for their fate in an increasingly warming Arctic.

Rabosky, Daniel L. ... et al.-- 4 pages, 3 figures, supplementary information https://doi.org/10.1038/s41586-018-0273-1, Far more species of organisms are found in the tropics than in temperate and polar regions, but the evolutionary and ecological causes of this pattern remain controversial1,2. Tropical marine fish communities are much more diverse than cold-water fish communities found at higher latitudes3,4, and several explanations for this latitudinal diversity gradient propose that warm reef environments serve as evolutionary ‘hotspots’ for species formation5,6,7,8. Here we test the relationship between latitude, species richness and speciation rate across marine fishes. We assembled a time-calibrated phylogeny of all ray-finned fishes (31,526 tips, of which 11,638 had genetic data) and used this framework to describe the spatial dynamics of speciation in the marine realm. We show that the fastest rates of speciation occur in species-poor regions outside the tropics, and that high-latitude fish lineages form new species at much faster rates than their tropical counterparts. High rates of speciation occur in geographical regions that are characterized by low surface temperatures and high endemism. Our results reject a broad class of mechanisms under which the tropics serve as an evolutionary cradle for marine fish diversity and raise new questions about why the coldest oceans on Earth are present-day hotspots of species formation, This work was supported in part by NSF grant DEB-1256330 (D.L.R.), an NSF DDIG grant to J.C. (DEB-1601830), an Encyclopedia of Life Rubenstein Fellowship to J.C. (EOL-33066-13) and by a Fellowship from the David and Lucile Packard Foundation (D.L.R.). P.F.C. was funded by a Gaylord Donnelley Postdoctoral Environment Fellowship (Yale) and through the ARC Centre of Excellence for Coral Reef Studies

Marine mammals are impacted by many anthropogenic activities and mitigating these impacts requires knowledge about the geographic occurrence of threats. Here, we systematically reviewed, categorized and geo-referenced information from >1780 publications about threats affecting 121 marine mammal species worldwide between 1991 and 2016. We created risk maps by assigning threat to countries where they had been reported, further refining spatial allocation to specific ocean basins and Longhurst biogeographical provinces and subsequent intersection with mapped species' distributions. We superimposed risk maps for different taxa and threats to visualize geographic patterns of risks and quantify risk severity with respect to number of species affected. Almost all marine mammal species have been reported to face at least one threat. Incidental catch affected the most species (112 species), followed by pollution (99 species), direct harvesting (89 species) and traffic-related impacts (86 species). Direct human activities, mainly fisheries, urban development, whaling/hunting and tourism were the major source of threats affecting most species (>60 species). Risk areas were identified for 51% of marine mammal core habitat. Besides, the majority of local marine mammal communities are at high-risk in 47% of world coastal-waters. Hotspots were located mainly in temperate and polar coastal waters and in enclosed seas such as the Mediterranean or Baltic Sea. However, risk areas differed by threat types and taxa. Our maps show that human activities in coastal waters worldwide impose previously unrecognized levels of cumulative risk for most of marine mammal species, and provide a spatially explicit frame of reference for the assessment of mammals' species conservation status.

Oscillations in the Earth’s temperature and the subsequent retreating and advancing of ice-sheets around the polar regions are thought to have played an important role in shaping the distribution and genetic structuring of contemporary high-latitude populations. After the Last Glacial Maximum (LGM), retreating of the ice-sheets would have enabled early colonizers to rapidly occupy suitable niches to the exclusion of other conspecifics, thereby reducing genetic diversity at the leading-edge. Bottlenose dolphins (genus Tursiops) form distinct coastal and pelagic ecotypes, with finer-scale genetic structuring observed within each ecotype. We reconstruct the postglacial colonization of the Northeast Atlantic (NEA) by bottlenose dolphins using habitat modeling and phylogenetics. The AquaMaps model hindcasted suitable habitat for the LGM in the Atlantic lower latitude waters and parts of the Mediterranean Sea. The time-calibrated phylogeny, constructed with 86 complete mitochondrial genomes including 30 generated for this study and created using a multispecies coalescent model, suggests that the expansion to the available coastal habitat in the NEA happened via founder events starting ~15 000 years ago (95% highest posterior density interval: 4 900–26 400). The founders of the 2 distinct coastal NEA populations comprised as few as 2 maternal lineages that originated from the pelagic population. The low effective population size and genetic diversity estimated for the shared ancestral coastal population subsequent to divergence from the pelagic source population are consistent with leading-edge expansion. These findings highlight the legacy of the Late Pleistocene glacial cycles on the genetic structuring and diversity of contemporary populations.

Increasing global energy demands have led to the ongoing intensification of hydrocarbon extraction from marine areas. Hydrocarbon extractive activities pose threats to native marine biodiversity, such as noise, light, and chemical pollution, physical changes to the sea floor, invasive species, and greenhouse gas emissions. Here, we assessed at a global scale the spatial overlap between offshore hydrocarbon activities and marine biodiversity (>25,000 species, nine major ecosystems, and marine protected areas), and quantify the changes over time. We discovered that two-thirds of global offshore hydrocarbon activities occur in areas within the top 10% for species richness, range rarity, and proportional range rarity values globally. Thus, while hydrocarbon activities are undertaken in less than one percent of the ocean's area, they overlap with approximately 85% of all assessed species. Of conservation concern, 4% of species with the largest proportion of their range overlapping hydrocarbon activities are range restricted, potentially increasing their vulnerability to localized threats such as oil spills. While hydrocarbon activities have extended to greater depths since the mid-1990s, we found that the largest overlap is with coastal ecosystems, particularly estuaries, saltmarshes and mangroves. Furthermore, in most countries where offshore hydrocarbon exploration licensing blocks have been delineated, they do not overlap with marine protected areas (MPAs). Although this is positive in principle, many countries have far more licensing block areas than protected areas, and in some instances, MPA coverage is minimal. These findings suggest the need for marine spatial prioritization to help limit future spatial overlap between marine conservation priorities and hydrocarbon activities. Such prioritization can be informed by the spatial and quantitative baseline information provided here. In increasingly shared seascapes, prioritizing management actions that set both conservation and development targets could help minimize further declines of biodiversity and environmental changes at a global scale.

In this Article, the affiliation of author Cristina Garilao was incorrectly given as ‘Evolutionary Biology and Ecology Laboratory, Albert Ludwigs University, Freiburg, Germany.’ (affiliation 8). It should be ‘GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany’ (affiliation 18). The original Article has been corrected online.

The IUCN (the International Union for Conservation of Nature) World Conservation Congress called for the full protection of 30% of each marine habitat globally and at least 30% of all the ocean. Thus, we quantitatively prioritized the top 30% areas for Marine Protected Areas (MPAs) globally using global scale measures of biodiversity from the species to ecosystem level. The analysis used (a) Ecosystems mapped based on 20 environmental variables, (b) four Biomes (seagrass, kelp, mangrove, and shallow water coral reefs) plus seabed rugosity as a proxy for habitat, and (c) species richness within each biogeographic Realm (indicating areas of species endemicity), so as to maximise representivity of biodiversity overall. We found that the 30% prioritized areas were mainly on continental coasts, island arcs, oceanic islands, the southwest Indian Ridge, the northern Mid-Atlantic Ridge, the Coral Triangle, Caribbean Sea, and Arctic Archipelago. They generally covered 30% of the Ecosystems and over 80% of the Biomes. Although 58% of the areas were within countries Exclusive Economic Zones (EEZ), only 10% were in MPAs, and

Here we demonstrate how to globally detect regions of high plankton diversity (the lower levels of the trophic chain) and also higher level consumers' diversity using satellite information of 'fluid dynamical niches' characterized by spatially and temporally different dominant plankton communities. The higher the spectral variability, the higher is the species community diversity, occupying different niches, regardless of the taxonomic group under consideration. Spectral heterogeneity is expected to be related to environmental heterogeneity and therefore is used as a powerful proxy of biodiversity. We calculate a diversity proxy using the PHYSAT algorithm on ocean color data as the heterogeneity of the water masses that it detects already integrate, in an explicit or implicit manner, the main information about the pigment, the size and the extruded compounds of the plankton and the biological meaningful physic-chemical characteristics of the water masses where the community develops. This study overcomes the classic problems of fragmented and heterogeneous information, combining biological and environmental context at different scales and making use of large-scale biodiversity databases combined with niche/trophic models and species distribution models (i.e. AQUAMAPS, ECCO2-Darwin, Seapodym). Biodiversity hotspots of consumers result significantly positively related with the remote sensed diversity of primary producers, top predators included.

Cold is better for polar predators Generally, biodiversity is higher in the tropics than at the poles. This pattern is present across taxa as diverse as plants and insects. Marine mammals and birds buck this trend, however, with more species and more individuals occurring at the poles than at the equator. Grady et al. asked why this is (see the Perspective by Pyenson). They analyzed a comprehensive dataset of nearly 1000 species of shark, fish, reptiles, mammals, and birds. They found that predation on ectothermic (“cold-blooded”) prey is easier where waters are colder, which generates a larger resource base for large endothermic (“warm-blooded”) predators in polar regions. Science , this issue p. eaat4220 ; see also p. 338

Mitochondrial DNA has been heavily utilized in phylogeography studies for several decades. However, underlying patterns of demography and phylogeography may be misrepresented due to coalescence stochasticity, selection, variation in mutation rates and cultural hitchhiking (linkage of genetic variation to culturally-transmitted traits affecting fitness). Cultural hitchhiking has been suggested as an explanation for low genetic diversity in species with strong social structures, counteracting even high mobility, abundance and limited barriers to dispersal. One such species is the sperm whale, which shows very limited phylogeographic structure and low mtDNA diversity despite a worldwide distribution and large population. Here, we use analyses of 175 globally distributed mitogenomes and three nuclear genomes to evaluate hypotheses of a population bottleneck/expansion vs. a selective sweep due to cultural hitchhiking or selection on mtDNA as the mechanism contributing to low worldwide mitochondrial diversity in sperm whales. In contrast to mtDNA control region (CR) data, mitogenome haplotypes are largely ocean-specific, with only one of 80 shared between the Atlantic and Pacific. Demographic analyses of nuclear genomes suggest low mtDNA diversity is consistent with a global reduction in population size that ended approximately 125,000 years ago, correlated with the Eemian interglacial. Phylogeographic analysis suggests that extant sperm whales descend from maternal lineages endemic to the Pacific during the period of reduced abundance and have subsequently colonized the Atlantic several times. Results highlight the apparent impact of past climate change, and suggest selection and hitchhiking are not the sole processes responsible for low mtDNA diversity in this highly social species.

Arctic animals face dramatic habitat alteration due to ongoing climate change. Understanding how such species have responded to past glacial cycles can help us forecast their response to today's changing climate. Gray whales are among those marine species likely to be strongly affected by Arctic climate change, but a thorough analysis of past climate impacts on this species has been complicated by lack of information about an extinct population in the Atlantic. While little is known about the history of Atlantic gray whales or their relationship to the extant Pacific population, the extirpation of the Atlantic population during historical times has been attributed to whaling. We used a combination of ancient and modern DNA, radiocarbon dating and predictive habitat modelling to better understand the distribution of gray whales during the Pleistocene and Holocene. Our results reveal that dispersal between the Pacific and Atlantic was climate dependent and occurred both during the Pleistocene prior to the last glacial period and the early Holocene immediately following the opening of the Bering Strait. Genetic diversity in the Atlantic declined over an extended interval that predates the period of intensive commercial whaling, indicating this decline may have been precipitated by Holocene climate or other ecological causes. These first genetic data for Atlantic gray whales, particularly when combined with predictive habitat models for the year 2100, suggest that two recent sightings of gray whales in the Atlantic may represent the beginning of the expansion of this species' habitat beyond its currently realized range.

In 2008, the Convention on Biological Diversity (CBD) adopted seven criteria to identify Ecologically or Biologically Significant Areas (EBSAs) “…in need of protection, in open ocean waters and deep sea habitats”. This paper reviews the history of the development of the “EBSA process”, which was originally driven by the commitment to establish marine protected areas in areas beyond national jurisdiction, but which has since broadened to encompass the possibility of informing marine spatial planning and other activities, both within and beyond national jurisdiction. Additionally, the paper summarizes ongoing efforts through CBD regional workshops to describe EBSAs and the development of the EBSA Repository, where information on these areas is to be stored. The overlap between the EBSA criteria and biodiversity criteria suites used by various authorities in areas beyond national jurisdiction is illustrated. The EBSA process has reached a critical juncture, whereby a large percentage of the global ocean has been considered by the regional workshops, but the procedure by which these areas can be incorporated into formal management structures has not yet been fully developed. Emerging difficulties regarding the mandate to describe, identify, endorse, or adopt EBSAs, are discussed.

Large marine protected areas (>30,000 km2) have a high profile in marine conservation, yet their contribution to conservation is contested. Assessing the overlap of large marine protected areas with 14,172 species, we found large marine protected areas cover 4.4% of the ocean and at least some portion of the range of 83.3% of the species assessed. Of all species within large marine protected areas, 26.9% had at least 10% of their range represented, and this was projected to increase to 40.1% in 2100. Cumulative impacts were significantly higher within large marine protected areas than outside, refuting the critique that they only occur in pristine areas. We recommend future large marine protected areas be sited based on systematic conservation planning practices where possible and include areas beyond national jurisdiction, and provide five key recommendations to improve the long-term representation of all species to meet critical global policy goals (e.g., Convention on Biological Diversity’s Aichi Targets).

Biodiversity and conservation data are generally costly to collect, particularly in the marine realm. Hence, data collected for a given-often scientific-purpose are occasionally contributed toward secondary needs, such as policy implementation or other types of decision-making. However, while the quality and accessibility of marine biodiversity and conservation data have improved over the past decade, the ways in which these data can be used to develop and implement relevant management and conservation measures and actions are not always explicit. For this reason, there are a number of scientifically-sound datasets that are not used systematically to inform policy and decisions. Transforming these marine biodiversity and conservation datasets into knowledge products that convey the information required by policy- and decision-makers is an important step in strengthening knowledge exchange across the science-policy interface. Here, we identify seven characteristics of a selection of online biodiversity and conservation knowledge products that contribute to their ability to support policy- and decision-making in the marine realm (as measured by e.g., mentions in policy resolutions/decisions, or use for reporting under selected policy instruments; use in high-level screening for areas of biodiversity importance). These characteristics include: a clear policy mandate; established networks of collaborators; iterative co-design of a user-friendly interface; standardized, comprehensive and documented methods with quality assurance; consistent capacity and succession planning; accessible data and value-added products that are fit-for-purpose; and metrics of use collated and reported. The outcomes of this review are intended to: (a) support data creators/owners/providers in designing and curating biodiversity and conservation knowledge products that have greater influence, and hence impact, in policy- and decision-making, and (b) provide recommendations for how decision- and policy-makers can support the development, implementation, and sustainability of robust biodiversity and conservation knowledge products through the framing of marine policy and decision-making frameworks.

RW collected the BC data with Raincoast Conservation Foundation, and was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (proposal no. 253407 (call reference: FP7‐PEOPLE‐2009‐IIF)) during the analysis stage. Despite lessons from terrestrial systems, conservation efforts in marine systems continue to focus on identifying priority sites for protection based on high species richness inferred from range maps. Range maps oversimplify spatial variability in animal distributions by assuming uniform distribution within range and de facto giving equal weight to critical and marginal habitats. We used Marxan ver. 2.43 to compare species richness-based systematic reserve network solutions using information about marine mammal range and relative abundance. At a global scale, reserve network solutions were strongly sensitive to model inputs and assumptions. Solutions based on different input data overlapped by a third at most, with agreement as low as 10% in some cases. At a regional scale, species richness was inversely related to density, such that species richness hotspots excluded highest-density areas for all species. Based on these findings, we caution that species-richness estimates derived from range maps and used as input in conservation planning exercises may inadvertently lead to protection of largely marginal habitat. Publisher PDF

Species distribution data provide the foundation for a wide range of ecological research studies and conservation management decisions. Two major efforts to provide marine species distributions at a global scale are the International Union for Conservation of Nature (IUCN), which provides expert-generated range maps that outline the complete extent of a species' distribution; and AquaMaps, which provides model-generated species distribution maps that predict areas occupied by the species. Together these databases represent 24,586 species (93.1% within AquaMaps, 16.4% within IUCN), with only 2,330 shared species. Differences in intent and methodology can result in very different predictions of species distributions, which bear important implications for scientists and decision makers who rely upon these datasets when conducting research or informing conservation policy and management actions. Comparing distributions for the small subset of species with maps in both datasets, we found that AquaMaps and IUCN range maps show strong agreement for many well-studied species, but our analysis highlights several key examples in which introduced errors drive differences in predicted species ranges. In particular, we find that IUCN maps greatly overpredict coral presence into unsuitably deep waters, and we show that some AquaMaps computer-generated default maps (only 5.7% of which have been reviewed by experts) can produce odd discontinuities at the extremes of a species' predicted range. We illustrate the scientific and management implications of these tradeoffs by repeating a global analysis of gaps in coverage of marine protected areas, and find significantly different results depending on how the two datasets are used. By highlighting tradeoffs between the two datasets, we hope to encourage increased collaboration between taxa experts and large scale species distribution modeling efforts to further improve these foundational datasets, helping to better inform science and policy recommendations around understanding, managing, and protecting marine biodiversity.

Habitat modifications driven by human impact and climate change may influence species distribution, particularly in aquatic environments. Niche-based models are commonly used to evaluate the availability and suitability of habitat and assess the consequences of future climate scenarios on a species range and shifting edges of its distribution. Together with knowledge on biology and ecology, niche models also allow evaluating the potential of species to react to expected changes. The availability of projections of future climate scenarios allows comparing current and future niche distributions, assessing a species' habitat suitability modification and shift, and consequently estimating potential species' reaction. In this study, differences between the distribution maps of 406 marine species, which were produced by the AquaMaps niche models on current and future (year 2050) scenarios, were estimated and evaluated. Discrepancy measurements were used to identify a discrete number of categories, which represent different responses to climate change. Clustering analysis was then used to automatically detect these categories, demonstrating their reliability compared to human supervised classification. Finally, the distribution of characteristics like extinction risk (based on IUCN categories), taxonomic groups, population trends and habitat suitability change over the clustering categories was evaluated. In this assessment, direct human impact was neglected, in order to focus only on the consequences of environmental changes. Furthermore, in the comparison between two climate snapshots, the intermediate phases were assumed to be implicitly included into the model of the 2050 climate scenario.

Whaling as a commercial enterprise is now defunct, not least due to the moratorium placed on it by the International Whaling Commission (IWC) almost 20 years ago. However, two distinct groups, one in favor of ‘sustainable’ whaling and one completely opposed to any killing of whales, continue to argue at the IWC and other political arenas. Almost ignored in this debate is the current growth of the whale watching industry, a logical alternative use for whale populations. Based on ecological and socio-economic criteria, the potential for whale watching is estimated for maritime countries that do not currently engage in this industry. Results suggest that whale watching could generate an additional 413 million USD (2009) in yearly revenue, supporting 5,700 jobs. Together with current global estimates, this would bring the total potential for the whale watching industry to over 2.5 billion USD in yearly revenue and about 19,000 jobs around the world. These results are discussed from an economic and conservation policy perspective, with emphasis on potential benefits and limitations.

There has been much recent discussion about the idea that large whales are potential competitors with fisheries for available marine resources. Based on this idea, often referred to as the ‘whales eat fish’ conflict, culling whales has been proposed as a way to increase resources available for human consumption and thereby ensuring global food security. However, the scientific basis for such arguments remains unclear, especially in the Caribbean waters where baleen whales generally do not feed. In this article, we (i) develop an ecosystem model describing the trophic interactions between whales, fish and fisheries in the Caribbean waters, (ii) calculate the level of overlap between cetaceans and fisheries for food resources, and (iii) simulate the removal of cetaceans from the Caribbean waters in order to quantify the potential increase in available biomass of commercially important fish. Ten groups of cetaceans are considered in the model, including baleen whales, toothed whales and small cetaceans. Our results suggest that baleen whales are not a threat to fisheries in Caribbean waters, while toothed cetaceans seem to be more impacted by fisheries than they actually impacting them. Whales target different types of food resources and consume significantly less than what is taken by fisheries. Moreover, simulated reductions in large whale abundance do not produce any appreciable increase in biomass of the commercially important fish species. In some cases, the presence of some whales actually improves fishery yield as a result of indirect predation effects.

Fourteen indicators of marine living resource management performance by country, reflecting both their intention to sustainably use the resource within their Exclusive Economic Zones and the effectiveness of their policies, were developed and the performances of 53 maritime countries were assessed. Four rankings of the countries, which jointly account for over 95 percent of the world's marine fisheries landings, are presented here as aggregated scores of the fourteen indicators, using different schemes for weighting the indicators, each reflective of the management preferences identified by the Global Environment Outlook 4 (GEO4) future development scenarios: Market First; Policy First; Security First; and Sustainability First. The resulting rankings differed substantially between the weighting schemes for the top performing countries but less so for the countries performing poorly.

There is global concern about the interaction between whales and fisheries, and in some countries, great whales are viewed as a threat to fisheries by potentially eating fish species that could be exploited for human consumption. We developed an ecosystem model to explore the trophic inter- actions between cetaceans and fisheries off Northwest Africa and to examine the potential impact of a reduction in the abundance of baleen whales on fishery yields. This allowed us to characterize the structure and function of the ecosystem in terms of biomass, mortalities, consumption rates, food habits, and fisheries. Faced with sparse data for our study area, we explicitly accounted for uncer- tainty in ecosystem structure, model accuracy, and input data and conducted an extensive sensitivity analysis. We tested model performance with time series of biomass and catches for important species of the system. Our results indicate that the overlap between prey species consumed by cetaceans and species targeted in fisheries is low. Furthermore, for a wide range of assumptions about whale abun- dances, diet composition, and food consumption in breeding areas, we found that whale consumption is several orders of magnitude lower than total fishery catches and 2 orders of magnitude lower than the amounts taken by other trophic groups. Finally, simulations of substantial reductions of whale populations did not influence the biomass of commercially important fish, nor any other species of the foodweb. These results suggest that fisheries yields would not benefit from the removal of whales in this area.

We present and evaluate AquaMaps, a presence-only species distribution modelling system that allows the incorporation of expert knowledge about habitat usage and was designed for maximum output of standardized species range maps at the global scale. In the marine environment there is a significant challenge to the production of range maps due to large biases in the amount and location of occurrence data for most species. AquaMaps is compared with traditional presence-only species distribution modelling methods to determine the quality of outputs under equivalently automated conditions. The effect of the inclusion of expert knowledge to AquaMaps is also investigated. Model outputs were tested internally, through data partitioning, and externally against independent survey data to determine the ability of models to predict presence versus absence. Models were also tested externally by assessing correlation with independent survey estimates of relative species abundance. AquaMaps outputs compare well to the existing methods tested, and inclusion of expert knowledge results in a general improvement in model outputs. The transparency, speed and adaptability of the AquaMaps system, as well as the existing online framework which allows expert review to compensate for sampling biases and thus improve model predictions are proposed as additional benefits for public and research use alike.

We present a new methodology for database-driven ecosystem model generation and apply the methodology to the world's 66 currently defined Large Marine Ecosystems. The method relies on a large number of spatial and temporal databases, including FishBase, SeaLifeBase, as well as several other databases developed notably as part of the Sea Around Us project. The models are formulated using the freely available Ecopath with Ecosim (EwE) modeling approach and software. We tune the models by fitting to available time series data, but recognize that the models represent only a first-generation of database-driven ecosystem models. We use the models to obtain a first estimate of fish biomass in the world's LMEs. The biggest hurdles at present to further model development and validation are insufficient time series trend information, and data on spatial fishing effort.

Fisheries targeting small-to-medium pelagic, so-called forage fish, impact on human food security and marine ecosystems. Because their operations are shrouded by the myth that forage fish are unsuitable for human consumption, the role of these fisheries in intensive food production is not well understood or appreciated. Thus, although they account for over 30% of global landings of marine fish annually, our knowledge of how these levels of removal impact on marine ecosystems is limited. Nevertheless, there is considerable scope for policy makers to change the current management of these fisheries and to enhance their contribution to food security and economic development. Industry and consumers also have an important role in finding the balance between these fisheries contributing to human food security and poverty alleviation on the one hand, and sustaining intensive animal food production systems, especially aquaculture, on the other.