The deep sea plays a critical role in global climate regulation through uptake and storage of heat and carbon dioxide. However, this regulating service causes warming, acidification and deoxygenation of deep waters, leading to decreased food availability at the seafloor. These changes and their projections are likely to affect productivity, biodiversity and distributions of deep‐sea fauna, thereby compromising key ecosystem services. Understanding how climate change can lead to shifts in deep‐sea species distributions is critically important in developing management measures. We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold‐water coral and commercially important deep‐sea fish species under present‐day (1951–2000) environmental conditions and to project changes under severe, high emissions future (2081–2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean. Our models projected a decrease of 28%–100% in suitable habitat for cold‐water corals and a shift in suitable habitat for deep‐sea fishes of 2.0°–9.9° towards higher latitudes. The largest reductions in suitable habitat were projected for the scleractinian coral Lophelia pertusa and the octocoral Paragorgia arborea, with declines of at least 79% and 99% respectively. We projected the expansion of suitable habitat by 2100 only for the fishes Helicolenus dactylopterus and Sebastes mentella (20%–30%), mostly through northern latitudinal range expansion. Our results projected limited climate refugia locations in the North Atlantic by 2100 for scleractinian corals (30%–42% of present‐day suitable habitat), even smaller refugia locations for the octocorals Acanella arbuscula and Acanthogorgia armata (6%–14%), and almost no refugia for P. arborea. Our results emphasize the need to understand how anticipated climate change will affect the distribution of deep‐sea species including commercially important fishes and foundation species, and highlight the importance of identifying and preserving climate refugia for a range of area‐based planning and management tools.

The diversity of life in the sea is critical to the health of ocean ecosystems that support living resources and therefore essential to the economic, nutritional, recreational, and health needs of billions of people. Yet there is evidence that the biodiversity of many marine habitats is being altered in response to a changing climate and human activity. Understanding this change, and forecasting where changes are likely to occur, requires monitoring of organism diversity, distribution, abundance, and health. It requires a minimum of measurements including productivity and ecosystem function, species composition, allelic diversity, and genetic expression. These observations need to be complemented with metrics of environmental change and socio-economic drivers. However, existing global ocean observing infrastructure and programs often do not explicitly consider observations of marine biodiversity and associated processes. Much effort has focused on physical, chemical and some biogeochemical measurements. Broad partnerships, shared approaches, and best practices are now being organized to implement an integrated observing system that serves information to resource managers and decision-makers, scientists and educators, from local to global scales. This integrated observing system of ocean life is now possible due to recent developments among satellite, airborne, and in situ sensors in conjunction with increases in information system capability and capacity, along with an improved understanding of marine processes represented in new physical, biogeochemical, and biological models.

Distribution and species composition of deep-sea sponge grounds of the Flemish Cap, Flemish Pass and the Grand Banks of Newfoundland are described based on Spanish/EU bottom trawl groundfish surveys between 40 and 1500 m depth. Four areas with large catches of sponges and at least 30 different species have been identified in the study area. Geodia barretti, Geodia macandrewii, Geodia phlegraei, Stryphnus ponderosus and Stelletta normani are the main structural sponges and constitute more than 94% of the total invertebrate biomass of these grounds. The temperature and salinity observed over these bottoms ranged between 3.38 and 3.84°C and between 34.85 and 34.90‰, respectively. The biomass of deep-water sponges per swept area was significantly higher on lightly or untrawled bottoms than in the grounds that are regularly fished. Data from trawl groundfish surveys cannot map the deep-sea sponge grounds to a precision less than the trawl distance of 1.5 nm. Nevertheless it has been used by the Northwest Atlantic Fisheries Organization (NAFO), along with additional Canadian data, to implement the 61/105 United Nations General Assembly Resolution in closing six areas to bottom fishing activities to protect the sponge grounds of the NAFO Regulatory Area.

Murillo, F. J., Durán Muñoz, P., Altuna, A., and Serrano, A. 2011. Distribution of deep-water corals of the Flemish Cap, Flemish Pass, and the Grand Banks of Newfoundland (Northwest Atlantic Ocean): interaction with fishing activities. – ICES Journal of Marine Science, 68: 319–332. The distribution of deep-water corals of the Flemish Cap, Flemish Pass, and the Grand Banks of Newfoundland is described based on bycatch from Spanish/EU bottom trawl groundfish surveys between 40 and 1500 m depth. In all, 37 taxa of deep-water corals were identified in the study area: 21 alcyonaceans (including the gorgonians), 11 pennatulaceans, 2 solitary scleractinians, and 3 antipatharians. The greatest diversity of coral species was on the Flemish Cap. Corals were most abundant along the continental slope, between 600 and 1300 m depth. Soft corals (alcyonaceans), sea fans (gorgonians), and black corals (antipatharians) were most common on bedrock or gravel, whereas sea pens (pennatulaceans) and cup corals (solitary scleractinians) were found primarily on mud. The biomass of deep-water corals in the bycatches was highest in previously lightly trawled or untrawled areas, and generally low in the regularly fished grounds. The information derived from bottom-trawl bycatch records is not sufficient to map vulnerable marine ecosystems (VMEs) accurately, but pending more detailed habitat mapping, it provides a valuable indication of the presence/absence of VMEs that can be used to propose the candidate areas for bottom fishery closures or other conservation measures.

In international fisheries management, scientific advice on the presence of ‘Vulnerable Marine Ecosystems’ (VMEs) per United Nations resolutions, has generally used qualitative assessments based on expert judgement of the occurrence of indicator taxa such as cold-water corals and sponges. Use of expert judgement alone can be criticised for inconsistency and sometimes a lack of transparency; therefore, development of robust and repeatable numeric methods to detect the presence of VMEs would be advantageous. Here, we present a multi-criteria assessment (MCA) method to evaluate how likely a given area of seafloor represents a VME. The MCA is a taxa-dependent spatial method that accounts for both the quantity and data quality available. This was applied to a database of records of VMEs built, held and compiled by the International Council for the Exploration of the Sea (ICES). A VME index was generated which ranged from 1.51 to 4.52, with 5.0 being reserved for confirmed VME habitats. An index of confidence was also computed that ranged from 0.0 to 0.75, with 1 being reserved for those confirmed VME habitats. Overall the MCA captured the important elements of the ICES VME database and provided a simplified, spatially aggregated and weighted estimate of how likely a given area is to contain VMEs. The associated estimate of confidence gave an indication of how uncertain that assessment was for the same given area. This methodology provides a more systematic and standardised approach for assessing the likelihood of presence of VMEs in the North-East Atlantic.

The effects of deep-sea bottom longlining on fish communities and the benthic ecosystem, as well as the interactions between fishing and seabirds, were studied based on data collected from a joint collaboration between the Spanish Institute of Oceanography and a longliner, carried out on the Hatton Bank area (north-east Atlantic) in 2008. A total of 38 longline sets were distributed mainly along the rugged bottom of the rocky outcrop at depths ranging from 750 to 1500 m. Deep-water sharks and lotids were predominant in the catches contributing respectively 80.4% and 13.1% in terms of weight. Deep-water sharks were predominant in the discards. By-catch of cold-water corals and small glass sponges occurred along the western flank of the Hatton Bank, while large hexactinellids were found along the eastern flank. Longlines fished the adult fraction of vulnerable deep-water sharks and lotids. High catches per unit effort values for these species were obtained in coral areas. A combination of seabird-scaring streamer lines and other measures of preventing seabird by-catch were used. Only one fulmar was captured and it survived. Data on distribution of marine litter and derelict deep-sea gillnets are also presented.