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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 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 services 1 , 2 , but at present only 2.7% of the ocean is highly protected 3 . 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 plans 4 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.

Climate change is exposing marine species to unsuitable temperatures while also creating new thermally suitable habitats of varying persistence. However, understanding how these different dynamics will unfold over time remains limited. We use yearly sea surface temperature projections to estimate temporal dynamics of thermal exposure (when temperature exceeds realised species’ thermal limits) and opportunity (when temperature at a previously unsuitable site becomes suitable) for 21,696 marine species globally until 2100. Thermal opportunities are projected to arise earlier and accumulate gradually, especially in temperate and polar regions. Thermal exposure increases later and occurs more abruptly, mainly in the tropics. Assemblages tend to show either high exposure or high opportunity, but seldom both. Strong emissions reductions reduce exposure around 100-fold whereas reductions in opportunities are halved. Globally, opportunities are projected to emerge faster than exposure until mid-century when exposure increases more rapidly under a high emissions scenario. Moreover, across emissions and dispersal scenarios, 76%-97% of opportunities are projected to persist until 2100. These results indicate thermal opportunities could be a major source of marine biodiversity change, especially in the near- and mid-term. Our work provides a framework for predicting where and when thermal changes will occur to guide monitoring efforts. Climate change is exposing marine species to unsuitable temperatures while also creating new thermal opportunities of varying persistence. Here, the authors examine how the interplay between these processes varies over time, demonstrating the potential of thermal opportunities to drive marine biodiversity changes, especially in the near and mid-term.

We present Part I of an annotated catalog of types in the Annelida collection of the Museum of Nature Hamburg, Leibniz Institute for the Analysis of Biodiversity Change. Part I includes the type specimens of 148 nominal species and subspecies belonging to Errantia incertae sedis and the Errantia clades Eunicida, Myzostomida, and Protodriliformia. The species are listed under these four groupings in alphabetical order by family and original binomen or trinomen. References to original descriptions, current accepted names, and remarks detailing additional information about type status and specimen condition are included.

Understanding species responses 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 subspecies. 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 modeling 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 subspecies, spatial genetic variation showed that porpoises from both sides of the North Atlantic form a continuous system belonging to the same subspecies (Phocoena phocoena phocoena). Yet, we identified important departures from random mating and restricted dispersal forming a highly significant isolation by distance (IBD) at both mtDNA and nuclear markers. A ten times stronger IBD at mtDNA compared with 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.

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 controversial 1 , 2 . Tropical marine fish communities are much more diverse than cold-water fish communities found at higher latitudes 3 , 4 , and several explanations for this latitudinal diversity gradient propose that warm reef environments serve as evolutionary ‘hotspots’ for species formation 5 – 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. Contrary to previous hypotheses, high-latitude fish lineages form new species at much faster rates than their tropical counterparts especially in geographical regions that are characterized by low surface temperatures and high endemism.

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 ~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.The authors develop a climate risk index for marine species under two emission scenarios and find that exploited species in low-income countries have the greatest risk under the high emissions scenario. Mitigating emissions reduces risks, enhances ecosystem stability and benefits low-income countries that depend on fisheries.

AbstractWe present Part I of an annotated catalog of types in the Annelida collection of the Museum of Nature Hamburg, Leibniz Institute for the Analysis of Biodiversity Change. Part I includes the type specimens of 148 nominal species and subspecies belonging to Errantiaincertae sedis and the Errantia clades Eunicida, Myzostomida, and Protodriliformia. The species are listed under these four groupings in alphabetical order by family and original binomen or trinomen. References to original descriptions, current accepted names, and remarks detailing additional information about type status and specimen condition are included.

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 lowlevels of genetic diversity and limited geographic structuring of genetic clades. We showthat narwhals experienced a long-termloweffective 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.

In fisheries, vulnerability assessments—also commonly known as ecological risk assessments (ERAs)—have been an increasingly popular alternative to stock assessments to evaluate the vulnerability of non-target species in resource- and data-limited settings. The widely-used productivity−susceptibility analysis (PSA) requires detailed species-specific biological information and fishery susceptibility for a large number of parameters to produce a relative vulnerability score. The two major disadvantages of PSA are that each species is assessed against an arbitrary reference point, and PSA cannot quantify cumulative impacts of multiple fisheries. This paper introduces an Ecological Assessment of the Sustainable Impacts of Fisheries (EASI-Fish), a flexible approach that quantifies the cumulative impacts of fisheries on data-limited bycatch species, demonstrated in eastern Pacific Ocean (EPO) tuna fisheries. The method first estimates fishing mortality (F) based on the ‘volumetric overlap’ of each fishery with the distribution of each species. F is then used in length-structured per-recruit models to assess population vulnerability status using conventional biological reference points. Model results were validated by comparison with stock assessments for bigeye and yellowfin tunas in the EPO for 2016. Application of the model to 24 species of epipelagic and mesopelagic teleosts, sharks, rays, sea turtles and cetaceans and identification of the most vulnerable species is demonstrated. With increasing demands on fisheries to demonstrate ecological sustainability, EASI-Fish allows fishery managers to more confidently identify vulnerable species to which resources can be directed to either implement mitigation measures or collect further data for more formal stock assessment.