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Carbonate mounds off Mauritania, Northwest Africa: status of deep-water corals and implications for management of fishing and oil exploration activities

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Cold-Water Corals and Ecosystems

Part of the book series: Erlangen Earth Conference Series ((ERLANGEN))

Abstract

Since 1998, Woodside Mauritania Pty Ltd has been exploring for hydrocarbon deposits offshore from the Islamic Republic of Mauritania, in Northwest Africa. A 3-D seismic survey, undertaken in 1999–2000, revealed the presence of buried and seabed carbonate mounds at approximately 450–550 m water depth on the continental slope. These mounds are approximately 100 m in height, 500 m wide at the base, and cover a linear extent of at least 190 km. Core samples from the mounds were found to contain dead fragments of four species of cold-water corals: Lophelia pertusa, Madrepora oculata, Solenosmilia variabilis and Desmophyllum sp. In 2002, a preliminary towed camera survey revealed large areas of coral rubble at two mound sites suggesting that corals were previously a dominant component of the benthic community. A second video survey, in 2003, recorded some live hard coral polyps and a single live coral colony, probably L. pertusa, at one of the mound sites. Coral rubble at all sites surveyed was found to support epibenthic invertebrate and fish assemblages. The mound areas surveyed may have been exposed to physical impacts that have resulted in damage of coral colonies previously inhabiting these features. Based on the nature of the damage and past and present demersal fishing activity in the region, bottom trawling could have caused these impacts. The discovery of a significant deep-water reefal system offshore Mauritania has implications for future management of trawling and oil exploration activities. These issues are discussed in the context of the potential biodiversity significance and conservation importance of the carbonate mud mounds and their associated biological communities.

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References

  • AFEN (2000) Atlantic margin environmental surveys of the seabed 1996 and 1998. UK Offshore Operators Assoc, CD-ROM ISBN 0-9538399-0-7

    Google Scholar 

  • BBG (2002) Video surveys of carbonate mounds in offshore Mauritania, July 2002. Bowman Bishaw Gorham, Rep R02084, Woodside Energy Ltd, Perth, Australia (unpublished)

    Google Scholar 

  • BBG (2004) Benthic surveys of the Chinguetti oil field and adjacent carbonate mounds, offshore Mauritania, July 2003. Rep R03005FR, Woodside Energy Ltd, Perth, Australia (unpublished)

    Google Scholar 

  • Cairns SD, Chapman RE (2001) Biogeographic affinities of the North Atlantic deep-water Scleractinia. In: Willison JHM, Hall J, Gass SE, Kenchington ELR, Butler M, Doherty P (eds) Proceedings of the First International Symposium on Deep-Sea Corals. Ecology Action Centre and Nova Scotia Museum, Halifax, Nova Scotia, pp 30–57

    Google Scholar 

  • Cervantes A, Goni R (1985) Descripcion de las pesquerias espanolas de merluzas y crustaceos de Africa Occidental al norte de cabo Blanco. Int Symp Upwelling off West Africa. Invest Pesqueras Barcelona 2: 825–850

    Google Scholar 

  • CNROP (1991) L’environnement, les resources et les pecheries de la Zee Mauritanienne. In: Chavance P, Girardin M (eds) Bull Centre Nat Rech Oceanogr Peches 23/1991. Ministere des Peches et de l’Economie Maritime, Nouâdhibou

    Google Scholar 

  • Croker PF, O’Loughlin O (1998) A catalogue of Irish offshore carbonate mud mounds. In: De Mol B (ed) Geosphere-biosphere coupling: carbonate mud mounds and cold-water reefs. Int Conf Sixth Post-Cruise Meet Training Through Res Programme. Gent, Belgium, 7–11 February 1998. Intergov Oceanogr Comm Workshop Rep 143, UNESCO

    Google Scholar 

  • De Mol B, Van Rensbergen P, Pillen S, Van Herreweghe K, Van Rooij D, McDonnell A, Huvenne V, Ivanov M, Swennen R, Henriet JP (2002) Large deep-water coral banks in the Porcupine Basin, southwest of Ireland. Mar Geol 188: 193–231

    Google Scholar 

  • Fosså JH, Mortensen PB, Furevik DM (2002) The deep-water coral Lophelia pertusa in Norwegian waters: distribution and fishery impacts. Hydrobiologia 471: 1–12

    Google Scholar 

  • Frederiksen R, Jensen A, Westerberg H (1992) The distribution of the scleractinian coral Lophelia pertusa around the Faroe Islands and the relation to internal tidal mixing. Sarsia 77: 157–171

    Google Scholar 

  • Freiwald A, Wilson JB, Henrich R (1999) Grounding Pleistocene icebergs shape recent deepwater reefs. Sediment Geol 125: 1–8

    Article  Google Scholar 

  • Fugro GEOS (1999) Current Regime Offshore Mauritania. Fugro GEOS Rep C50075, Woodside Energy Ltd, Perth, Australia (unpublished)

    Google Scholar 

  • GeoSed (2002) Preliminary geohazards study Chinguetti Cluster Development, Mauritania. GeoSed Ltd, Rep 2002/03, Woodside Energy Ltd, Perth, Australia (unpublished)

    Google Scholar 

  • Hall-Spencer J, Allain V, Fosså JH (2002) Trawling damage to Northeast Atlantic ancient coral reefs. Proc R Soc London B 269: 507–511

    Google Scholar 

  • Henriet JP, De Mol B, Pillen S, Vanneste M, Van Rooij D, Versteeg W, Croker PF, Shannon PM, Unnithan V, Bouriak S, Chachkine P (1998) Gas hydrate crystals may help build reefs. Nature 391: 648–649

    Article  Google Scholar 

  • Hovland M, Croker PF, Martin M (1994) Fault-associated seabed mounds (carbonate knolls?) off western Ireland and North-west Australia. Mar Petrol Geol 11: 232–246

    Article  Google Scholar 

  • Hovland M, Mortensen PB, Brattegard T, Strass P, Rokoengen K (1998) Ahermatypic coral banks off mid-Norway: evidence for a link with seepage of light hydrocarbons. Palaios 13: 189–200

    Google Scholar 

  • Huvenne VAI, De Mol B, Henriet JP (2003) A 3D seismic study of the morphology and spatial distribution of buried mounds in the Porcupine Basin. Mar Geol 198: 5–25

    Article  Google Scholar 

  • Kenyon N, Akhmetzhanov AM, Wheeler AJ, van Weering TCE, de Haas H, Ivanov MK (2003) Giant carbonate mounds in the southern Rockall Trough. Mar Geol 195: 5–30

    Article  Google Scholar 

  • Maigret C (1985) Les stocks de Palinuridae de la cote nord-ouest africaine. Int Symp Upwelling off West Africa. Invest Pesqueras Barcelona 2: 977–987

    Google Scholar 

  • Masson DG, Bett BJ, Billett DSM, Jacobs CL, Wheeler AJ, Wynn RB (2003) The origin of deep-water, coral-topped mounds in the northern Rockall Trough, Northeast Atlantic. Mar Geol 194: 159–180

    Article  Google Scholar 

  • McDonough JJ, Puglise KA (2003) Summary: Deep-Sea Corals Workshop. International Planning and Collaboration Workshop for the Gulf of Mexico and the North Atlantic Ocean. Galway, Ireland, January 16–17, 2003. US Dept Commerce, NOAA Tech Memo NFMS-F/SPO-60, 51 pp

    Google Scholar 

  • Minas HJ, Codispoti LA, Dugdale RC (1982) Nutrients and primary production in the upwelling region off Northwest Africa. Rapp P-v Réun Cons Int Explor Mer 180: 148–183

    Google Scholar 

  • Mittlesteadt E (1983) The upwelling area off Northwest Africa — a description of phenomena related to coastal upwelling. Progr Oceanogr 12: 307–331

    Google Scholar 

  • Mittlesteadt E (1991) The ocean boundary along the northwest Africa coast: circulation and oceanographic properties at the sea surface. Progr Oceanogr 26: 307–355

    Google Scholar 

  • Mortensen PB, Hovland M, Brattegard T, Farestveit R (1995) Deep water bioherms of the scleractinian coral Lophelia pertusa (L.) at 64°N on the Norwegian Shelf: structure and associated megafauna. Sarsia 80: 145–158

    Google Scholar 

  • Mortensen PB, Hovland M, Fosså JH, Furevik D (2001) Distribution, abundance and size of Lophelia pertusa coral reefs in mid-Norway in relation to seabed characteristics. J Mar Biol Ass UK 84: 581–597

    Google Scholar 

  • Oceanic Development (2002) Fisheries Assessment Study Mauritania. Final Report by Oceanic Development in association with Promoconsult, with the support of IMROP, for Woodside Australian Energy, October 2002 (unpublished)

    Google Scholar 

  • O’Reilly BM, Readman PW, Shannon PM, Jacob AWB (2003) A model for the development of a carbonate mound population in the Rockall Trough based on deep-towed sidescan sonar. Mar Geol 198: 55–66

    Google Scholar 

  • Puglise KA, Brock RJ, McDonough JJ (2005) Identifying critical information needs and developing institutional partnerships to further the understanding of Atlantic deep-sea coral ecosystems. In: Freiwald A, Roberts JM (eds) Cold-water Corals and Ecosystems. Springer, Berlin Heidelberg, pp 1129–1140

    Google Scholar 

  • Ramos A, Fernandez L, Gonzalez R (1998) The black hake fishery in the Mauritanian EEZ: analysis of the possible application of a 30 cm minimum. Informes Tecnicos. Inst Espan Oceanogr 173, 40 pp

    Google Scholar 

  • Roberts JM, Long D, Wilson JB, Mortensen PB, Gage JD (2003) The cold-water coral Lophelia pertusa (Scleractinia) and enigmatic seabed mounds along the north-east Atlantic margin: are they related? Mar Pollut Bull 46: 7–20

    Google Scholar 

  • Rogers AD (1999) The biology of Lophelia pertusa (Linnaeus, 1758) and other deep-water reef-forming corals and impacts from human activities. Int Rev Hydrobiol 84: 315–406

    Google Scholar 

  • Roy C (1992) Réponses des stocks de poissons pélagiques à la dynamique des upwellings en Afrique de l’ouest: analyse et modélisation. ORSTOM, Paris, 146 pp

    Google Scholar 

  • Sobrino I, Garcia T (1991) Analisis y descripcion de las pesquerias de crustaceos decapodos en agues de la republica islamica de Mauritania durante el periodo 1987–1990. Informes Tecnicos. Inst Espan Oceanogr 112, 18 pp

    Google Scholar 

  • Sobrino I and Garcia, T (1997) Analisis de los Descartes producidos por la flota Espanola en la pesqueria de crustaceos decapodos en agues de la republica islamica de Mauritania. Informes Tecnicos. Inst Espan Oceanogr 166, 24 pp

    Google Scholar 

  • Van Weering TCE, de Haas H, De Stigter HC, Lykke-Andersen H, Kouvaev I (2003) Structure and development of giant carbonate mounds at the SW and SE Rockall Trough margins, NE Atlantic Ocean. Mar Geol 198: 67–81

    Google Scholar 

  • Wheeler AJ, Bett, BJ, Billett DSM, Masson DG, Mayor D (in press) The impact of demersal trawling on NE Atlantic deep-water coral habitats: the case of the Darwin Mounds, UK. In: Thomas J, Barnes P (eds) Benthic Habitats and the Effects of Fishing. Amer Fish Soc, Bethesda, Maryland, USA

    Google Scholar 

  • Wheeler AJ, Kozachenko M, de Haas H, Henriet JP, Huvenne V, Masson DG, Olu-Le Roy K (submitted) Hydrodynamically influenced small deep-water reefs (Moira Mounds) in the Porcupine Seabight, NE Atlantic. Int J Earth Sci

    Google Scholar 

  • Wilson JB (1979) The distribution of the coral Lophelia pertusa (L.) [L. prolifera (Pallas)] in the north-east Atlantic. J Mar Biol Soc UK 59: 149–164

    Google Scholar 

  • WNI (2002) Mauritania Development metocean measurements, August to December 2002. Rep R1152, Woodside Energy Ltd, WNI Oceanographers & Meteorologists, Australia (unpublished)

    Google Scholar 

  • Woodside (2002) Mauritania integrated remote sensing and seabed studies. Rep VT00092, Woodside Energy Ltd, Perth, Australia (unpublished)

    Google Scholar 

  • Wynn RB, Masson DG, Stow DAV, Weaver PE (2000) The Northwest African slope apron: a modern analogue for deep-water systems with complex seafloor topography. Mar Petrol Geol 17: 253–265

    Article  Google Scholar 

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Colman, J.G., Gordon, D.M., Lane, A.P., Forde, M.J., Fitzpatrick, J.J. (2005). Carbonate mounds off Mauritania, Northwest Africa: status of deep-water corals and implications for management of fishing and oil exploration activities. In: Freiwald, A., Roberts, J.M. (eds) Cold-Water Corals and Ecosystems. Erlangen Earth Conference Series. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-27673-4_21

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