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More than 27 species of deep-sea corals have been identified off Atlantic Canada but their distributions are largely unknown. Bottom trawling is recognized as a threat to deep-sea corals in Atlantic Canada but the degree of damage has not been quantified. It is difficult to assess the level of conservation required for these organisms without basic information about their distribution. This study attempts to improve our knowledge of the distribution of deep-sea corals in Atlantic Canada. The study uses three sources of data to map the distribution of deep-sea corals in Atlantic Canada including the Canadian Department of Fisheries and Oceans (DFO) groundfish trawl surveys from 1999–2001, DFO fisheries observer records from 2000 and 2001, and local ecological knowledge of fishermen in northern Nova Scotia and Newfoundland. The results reveal that deep-sea corals are widely distributed along the edge of the continental shelf from the Gulf of Maine to the Davis Strait. The study confirms the presence of eight species including: Acanella arbuscula, Acanthogorgia armata, Flabellum spp., Keratoisis ornata, Lophelia pertusa, Paragorgia arborea, Paramuricea spp. and Primnoa resedaeformis . Significant findings from the study include: documentation of an antipatharian, an order not previously recorded in Atlantic Canada; documentation of L. pertusa from the Stone Fence and reported locations from Jordan Basin and the Gully; and the extension of the known ranges of P. arborea, K. ornata , and Paramuricea spp. Relatively high abundances of P. resedaeformis and P. arborea are reported from the Northeast Channel off southwest Nova Scotia and east of Cape Chidley, Labrador. The highest coral species richness is found along the edge of the continental shelf between the Gully and the Laurentian Channel at the edge of the Scotian Shelf. Fishermen reported catching the largest specimens and highest numbers of corals from the Stone Fence and also identified the Gully as an area of high coral abundance. Several fishermen reported significant changes to the seafloor on the eastern Scotian Shelf and the Stone Fence over the duration of their fishing careers, including a decrease in the size and number of corals they caught.

Submarine canyons are structurally complex habitats known to support high densities and diversity of megafaunal organisms. This study describes deepwater corals and their habitats in The Gully, the largest submarine canyon in eastern North America, situated at the Canadian margin off Nova Scotia. Video recordings of the seabed were made along 49 transects, at depths between 110 and 544 m, using a tethered video camera system. The Gully has a high diversity of habitats with steep bedrock outcrops, high relief bottom with ledges of semi-consolidated mudstone, as well as level soft bottoms and areas with gravel. In total 95 megafaunal taxa were observed of which 16 species were corals. There was a strong, positive correlation between the total number of megafaunal taxa and number of coral species along transects, suggesting that coral diversity is a good indicator for overall megafaunal diversity. Corals were present in most parts of the canyon, and up to 11 species were observed along a single transect. The distribution patterns of corals were mainly related to distance along the axis from the canyon head and type of seabed substratum. The highest abundance of corals was found on the western side in the outer part of the canyon and is probably related to circulation patterns with a higher load of particulate matter in the out-fl owing water. Nephtheid soft corals, mainly Duva florida , were most frequent and were found within the whole depth range. Gorgonian corals were observed only deeper than 340 m. Except for Acanella arbuscula and Radicipes gracilis , which are anchored in mud, the gorgonians were mainly confined to areas with cobble and boulder and in a few cases to semiconsolidated mudstone. Multivariate analyses were applied to identify groups of transects and species, and to indicate which environmental factors control the distribution of corals and other megafauna in The Gully.

A database of deep-water alcyonacean records has been assembled using information that reaches back to the work of A.E. Verrill from the 1800s. These database records fall into two time periods, those from 1874 to 1920, and from 1950 to 2001. A total of 25 species in 10 families are so far known from the northeastern U.S. Most of these species are common in deeper waters of the continental shelf, with a few being restricted to the canyons and other slope environments. A comparison of western and eastern North Atlantic records indicates there is little similarity between the regions. In the cold-temperate to boreal part of the region there is about 41 % similarity of the “stoloniferous” and “massive body” soft coral species, but only about 28 % similarity amongst all the “gorgonian” species. In the warm temperate part of the region the similarity for all groups is less than 10 %. Deep-water alcyonaceans are strongly impacted by bottom fishing gear so it is likely that modern distributional records will not be exactly similar to those from deep in the past.

One of the critical information needs identified at the 2003 Deep-Sea Corals Workshop in Galway, Ireland, was to locate and chart deep-sea corals in order to develop reliable estimates of their distribution and abundance. While reports of deep-sea corals from the Gulf of Mexico date back to the 1860s, relatively little is known about their distribution or abundance. This paper attempts to provide a current assessment of the occurrence of Lophelia pertusa and Madrepora oculata in water depths greater than 200 m in the Gulf of Mexico by summarizing records from (1) published material, (2) the 2003 National Museum of Natural History Taxonomic Database, (3) findings obtained during the September-October 2003 NOAA-OE RV Ronald H. Brown cruise RB-03-07-leg-2 in the northern Gulf, and (4) from various unpublished sources.

As a result of the explorations carried out by the Colombian Marine and Coastal Research Institute (INVEMAR) between 1998–2002 along the Colombian Caribbean continental shelf and upper slope, the occurrence of azooxanthellate coral banks was suspected at three sites (from the northern to southern Colombian Caribbean coast): off La Guajira Peninsula, at a water depth of 70 m; off Santa Marta, at 200 m, and nearby the San Bernardo Archipelago, at 150 m). Each site exhibited particular bottom features (relief and substrate), suggestive of reef structures. The analysis of the fauna collected by bottom trawling at these sites showed that many of the fishes, mollusks, echinoderms, crustaceans, antipatharians, soft corals and bryozoans collected are characteristic dwellers of hard substrates or reef bottoms. At the first site (Guajira) the hard coral Cladocora debilis , was the most abundant; a total of 156 species of invertebrates and fishes were identified among the material collected at this site. At the second site (Santa Marta), 13 scleractinian species were collected, but Madracis myriaster , was the dominant species; another 102 species of invertebrates and fishes were also found. At the third site (San Bernardo) 19 scleractinian species were found, M. myriaster being the dominant. A total of 135 species of invertebrates and fishes were collected at this site. It is presumed that deep-sea coral banks have developed in these three settings, since many of the collected species are known to be hard or reef bottom dwellers.

We define habitat-forming deep-sea corals as those families of octocorals, hexacorals, and stylasterids with species that live deeper than 200 m, with a majority of species exhibiting complex branching morphology and a sufficient size to provide substrata or refugia to associated species. We present 2,649 records (name, geoposition, depth, and data quality) from eleven institutions on eight habitatforming deep-sea coral families, including octocorals in the families Coralliidae, Isididae, Paragorgiidae and Primnoidae, hexacorals in the families Antipathidae, Oculinidae and Caryophylliidae, and stylasterids in the family Stylasteridae. The data are ranked according to record quality. We compare family range and distribution as predicted by historical records to the family extent as informed by recent collections aboard the National Oceanic of Atmospheric Administration (NOAA) Office of Ocean Exploration 2002 Gulf of Alaska Seamount Expedition (GOASEX). We present a map of one of these families, the Primnoidae. We find that these habitat-forming families are widespread throughout the Northeast Pacific, save Caryophylliidae ( Lophelia sp.) and Oculinidae ( Madrepora sp.), which are limited in occurrence. Most coral records fall on the continental shelves, in Alaska, or Hawaii, likely reflecting research effort. The vertical range of these families, based on large samples ( N >200), is impressive. Four families have maximum-recorded depths deeper than 1500 m, and minimum depths shallower than 40 m. Isidid, primnoid, and antipatharian records all exceed 2500 m depth. GOASEX collections are made from each of seven seamounts surveyed, extending the known range of Coralliidae 2500 km northward and the known limits of Isididae 450 km seaward, beyond the continental shelf, to seamounts in the Gulf of Alaska.

The benthic deep-water coral fauna of the Shiribeshi Seamount, Japan, was examined using the JAMSTEC video archives of four submersible dives in July 2001. An observational dataset containing n = 2055 records was obtained. The vertical distributions of the deep-water gorgonians Family Primnoidae and Paragorgiidae were determined. Primnoid corals include at least one species, Primnoa resedaeformis pacifica (Kinoshita, 1907) and are distributed between 1030 m and 271 m in depth and at a water temperature of 0.24–1.11°. Paragorgiid corals were observed between 491 m and 178 m in depth and at a water temperature of 0.66–1.69°, in shallower and warmer areas than primnoid species. It was observed that deep-sea gorgonians on the Shiribeshi Seamount in the North-West Pacific region exhibit family zonation and vertical distribution patterns. The distribution of hydrocorals, unidentified sponges, shrimp, and nudibranchs was also recorded. This is the first report on a deep-sea gorgonian coral community inhabiting Japanese waters.

The Institute of Marine Research commenced a program for mapping and assessment of Lophelia reefs in 1997. It was initiated by reports from fishermen claiming that bottom trawling damaged deep-water coral reefs. The strategy was to survey coral sites reported in the literature and by the fishermen. This has provided an extensive database of coral occurrences, both damaged and undamaged sites. A number of major coral reefs have been identified, which has provided a better understanding of the morphology of Lophelia reefs and where they are likely to occur. We are now able to identify potential coral areas by analysing seafloor topography on maps. Fast and reliable ground-truthing methods using simple and inexpensive systems have been developed. Mapping and quantification of corals demand more advanced instrumentation, such as singlebeam and multibeam echo sounders in combination with data processing software allowing coral reefs to be detected in real time. Systems providing real time presentation of multibeam data are especially useful in combination with Remotely Operated Vehicle (ROV) positioned with acoustic navigation systems. We suggest the following mapping procedure: 1) acoustical reef detection followed by multibeam mapping, preferably along with collection of seismic reflection data. 2) ground-truthing with a tethered video camera platform or an ROV. The position of the observation platform is plotted online and draped on the multibeam maps, either in 2D or 3D mode. Examples from the reefs on Sula, Røst, Træna and Fugløy are given.

An overview of preliminary results from a series of recent Remotely Operated Vehicle (ROV) dives on the deep-water coral provinces of the Porcupine Bank, Irish continental margin, NE Atlantic is presented. The Porcupine Bank exhibits numerous giant carbonate mounds (up to 100s of metres in height) that occur predominantly, although not exclusively, on topographic ridges. The results revealed that, although these ridges have a tectonic origin, contemporaneous activity is typified by erosion due to strong hydrodynamic controls. The carbonate mounds are colonized by a variety of suspension feeders and associated fauna including framework-building corals (e.g., Lophelia pertusa and Madrepora oculata ) although dense coral reef-like fauna coverage is not evident at present. The ecology of the carbonate mounds varied widely. Sessile megafauna, such as sponges, gorgonians and framework-building corals (e.g., Lophelia pertusa ), were abundant on some of the carbonate mounds. Other mounds were relatively barren and appeared to be undergoing a natural senescence, with a much lower biomass of megafauna than is typical of shallow-water coral reefs. Some mounds had been damaged by demersal trawls, with smashed coral and lost gear common, whereas others appeared relatively pristine with occasional evidence of man-made litter.

The Belgica Mound province is one of three provinces where carbonate mounds are associated with cold-water coral species in Porcupine Seabight, west of Ireland. Building upon extensive existing datasets, the Polarstern ARK XIX/3a cruise, deploying the robotic submersible VICTOR6000 (ROV), was undertaken in June 2003. This paper presents an overview of preliminary results from a reconnaissance video survey over and between several steep-flanked Belgica Mounds (giant mounds) and from a microbathymetric survey over some smaller mounds (Moira Mounds). Visual evidence for a strong hydrodynamic regime in the vicinity of the carbonate mounds is found with the interaction between currents and sedimentation having an important role in mound growth and development. Only some mounds show a high percentage of live coral coverage although there is a clear increase of megafaunal concentrations and species on mounds. One area of the province (the eastern ridge of aligned mounds) revealed very little live coral cover, asymmetrical drift accumulations burying the eastern sides and sediment-clogged dead coral frameworks at the western sides. This is in contrast to other areas (e.g., the western alignment of mounds) that show abundant live coral cover at present. In nearly all parts of the survey area the impact of fisheries, especially demersal trawling, is noted.