In a descriptive study of megafauna of several Southeast Atlantic seamounts, multiple video-transects on upper slopes and summits documented the occurrence of benthic invertebrate taxa, primarily corals, regarded as indicators of vulnerable marine ecosystems (VMEs) as defined in international guidelines. At Schmitt-Ott Seamount there was a pronounced dominance of gorgonian corals (seafans, Alcyonacea). In all other study areas the diversity was greater, and more scleractinians (stony corals, Scleractinia) were observed. Scleractinian corals were mainly dead, and much of the coral framework and rubble may have been ancient. In the Valdivia complex and on Ewing Seamount, which are open to fisheries, scleractinians seemed restricted to some slopes of knolls, and on Valdivia Bank and the subarea denoted Valdivia West the summit substrate was mostly bare rock. Pelagic armourhead Pseudopentaceros richardsoni and splendid alfonsino Beryx splendens (two targets of commercial fisheries in the area) were observed at a few sites, but did not appear to be abundant in the main former fishing areas of the Valdivia area. Orange roughy Hoplostethus atlanticus was common in video records around the summit at Ewing Seamount. The deep-sea red crab Chaceon erytheiae was abundant in the Valdivia area and at Ewing Seamount, and crabs were distributed across a more extensive depth range than the fishes. In areas with high densities of live coral, the video records suggested that the benthic communities were intact and not impacted by fishing. Evidence of past fishing activities included observations of lost pots and rope at Vema Seamount and in the Valdivia area.

Most of the Southeast Atlantic Ocean is abyssal, and global bathymetries suggest that only similar to 3.2% of the areas beyond national jurisdiction (ABNJ; also known as the high seas, as defined in the United Nations Convention on the Law of the Sea [UNCLOS]) are shallower than 2 500 m. This study mapped bathymetry and characterised substrates in selected seamount summit areas, including several that have been or may become fishing areas. The southernmost location, the Schmitt-Ott Seamount, has exposed volcanic bedrock with surrounding flats covered by thin biogenic sediments and/or coral rubble that appears ancient. At Wust, Vema, Valdivia and Ewing seamounts the basaltic base appears to be overlain by coral caps and other coral substrates (sheets, rubble). Adjacent summit plains have biogenic sediments of varying thickness. Vema has a flat, roughly circular summit, <100 m deep, with the shallowest point being a 22-m-deep summit knoll; the upper slopes have ancient coral framework, but the summit has a mixture of coralline and volcanic rock and coarse sediments, including extensive areas with coralline algae and kelp forests. Valdivia Bank is a 230-m-deep, flat, rocky area (similar to 11 x 5 km), protruding steeply from the extensive multi-summit Valdivia subarea of the Walvis Ridge. The distribution of past fisheries in the Convention Area of the South East Atlantic Fisheries Organisation (SEAFO) was considered in relation to the new information on bathymetry and substrate.

Distributions of deep-sea fish, benthic invertebrates and the effects of deep-sea bottom trawling were studied based on data collected in 2005 from a joint collaboration survey undertaken between the Spanish Institute of Oceanography and a deep-sea trawler on the Hatton Bank (north-east Atlantic). A total of 163 valid bottom trawl hauls (600–1600 m) were analysed. The main trawlable grounds were located on the sedimentary seabed of the western flank of the bank (Hatton Drift). Grenadiers and smoothheads were predominant in the trawl catches (67% and 11.8% by weight respectively). Both species were abundant along the western flank. Deep-water sharks accounted for 7.4% of weight, and were abundant along the south-eastern slopes. Chimerids, lotids, morids and other deep-sea species were also taken as by-catch. Grenadiers and deep-water sharks dominated the discards. By-catches of cold-water corals were generally associated with the rocky outcrop and were more abundant at the top of the bank. Abundant by-catches of large sponges, characteristic of sponge-dominated biotopes, were taken from the eastern flank.

In reply to the United Nations General Assembly Resolutions on sustainable fisheries, Spain, either by itself or in collaboration with other Nations, has been carrying out studies on vulnerable marine ecosystems (VMEs) in the high seas of the Atlantic Ocean (areas beyond national jurisdictions) since 2005. Such studies provide advice to the Spanish Government, the Regional Fisheries Management Organizations and the European Union. This paper presents the multidisciplinary methodology used and summarises the following management results: (i) contribution to identification of cold-water corals and provision of evidence to close part (∼16,000km2) of the Hatton Bank (NE Atlantic) to bottom fishing; (ii) compilation of an international data base to identify VMEs on the slopes of the Grand Banks of Newfoundland, Flemish Pass, and Flemish Cap (NW Atlantic) and to redefine areas currently closed to fishing; (iii) improvement of knowledge about deepwater ecosystems on Walvis Ridge and adjacent seamounts (SE Atlantic) as a pilot project for implementation in this region; and (iv) identification of VMEs and closure of an area (∼41,300km2) on the high seas of the SW Atlantic. Also discussed are progress and challenges related to identifying and protecting VMEs.

The present paper provides an overview of cold-water corals protection in the Hatton Bank deep-water fisheries through the implementation of the United Nations General Assembly resolution 61/105. The methodology and scientific evidence used to propose protection of cold-water coral ecosystems in the high seas (∼16,000km2) are briefly summarised. The role of international agents and importance of interdisciplinary research for making management decisions are furthermore described. Implementation was slow because (i) of scarce initial scientific knowledge, (ii) research on the high seas was difficult and expensive, (iii) there were several international interests at stake, (iv) agreement from a number of agents was needed, and (v) international advisory and decision making processes were quite slow. Some lessons learned are also discussed since these may help to increase protection efficiency of deep-sea vulnerable marine ecosystems in the high seas.

This work is focused on the relationship between the morphology of the sea bed and the habitats of invertebrate benthic species. The study area is located between 600 and 2000 m water depth on the western slope of Hatton Bank (NE Atlantic Ocean). Acoustic methods as well as sea bed sampling were used to carry out this work. Two major sea bed domains have been described: Outcrop (mainly comprised by hard substrate) and Drift (in the main, composed by mobile sediment). Benthic communities are sparse where the sea bed comprises mobile sediments, such as the Hatton Drift in the deeper water, and more common where the sea bed comprises a hard rocky substrate, as observed in shallower water on the top of Hatton Bank.

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.

The Spanish interdisciplinary research project ECOVUL/ARPA focuses on the western slope of Hatton Bank (NE Atlantic Ocean). As part of this project, interpretation of multibeam bathymetry data, very high resolution seismic profiles and sediment samples collected by the Instituto Espanol de Oceanografia, permitted to identify the Talisman Slide, an underwater landslide developed within the deepwater sediments of the Hatton Drift. Within the slipped mass, present day sea-bed morphology is rough, comprising blocks, ridges, steps and secondary slides. Seismic profiles show the slide mass to be supported by a sequence of contouritic deposits. Trigger mechanism for the Talisman Slide is likely a combination of several causative factors such as erosion (caused by bottom currents) and an earthquake event which accelerated the slide process.