Listed below is background material on the
Celtic-Biscay Shelf Large Marine Ecosystem. To keep this site up-to-date,
users are requested to provide relevant information or links to the LME webmaster .
Brief Description:
The Celtic-Biscay Shelf Large Marine Ecosystem
is situated in the Northeast Atlantic Ocean and has a temperate climate.
At its southern limit the shelf is steep and narrow, but it widens steadily
along the West coast of France, merging with the broad continental shelf surrounding
Ireland and Great Britain. Four countries, Ireland, Great Britain, France
and Spain, border the LME. The Celtic-Biscay Shelf is characterized by a
strong interdependence of human impact and biological and climate cycles (see
Koutsikopoulos and Le Cann, 1996). The main book chapter pertaining to this
LME is Valdes and Lavin, 2002, on the Bay of Biscay..
I. Productivity:
This LME’s dynamic is governed by climate and tides. For a map of the Bay of Biscay, see Valdes and Lavin, 2002, p. 294. The LME is influenced by the North Atlantic Drift in the North, and by the Azores Current in the South. For information on circulation and currents, see Koutsikopoulos and Le Cann, 1996. The region undergoes a seasonal climatic cycle that strongly affects the pelagic ecosystem through forcing factors: sunlight exposure, heat input, and mechanical forcing on the surface due to wind. For more information on seasonal variability, the vertical structure of coastal and oceanic waters, river plumes, coastal runoff and tidal fronts, see Valdes and Lavin, 2002. For a map of temperature distribution in the Bay of Biscay, in Valdes and lavin, 2002, p. 297. The Celtic-Biscay Shelf LME is considered a Class I, highly productive (>300 gC/m2-yr) ecosystem based on SeaWiFS global primary productivity estimates. Living marine resources include a wide range of organisms. In terms of biogeography, the LME is a region of transition and there is a richness in floral and faunal species. It is difficult to determine the states of equilibrium of species and communities. Natural variability occurs on a wide range of space and time scales (seasonal, inter-annual, decadal and centennial cycles). This LME is positioned in the eastern section of the North Atlantic, and therefore is in the area of the cyclical oscillations of the North Atlantic Oscillation (NAO). For more information on coastal upwelling, and on the warm and salty current called Navidad, see Valdes and Lavin, 2002.
The natural variability of this LME adds a high degree of uncertainty to the management of marine resources. The marine resources exploited in the LME include molluscs, whales, seaweeds, herring, redfish, sand eels, and mackerel. The FAO 10-year trend shows a decrease from 1,150,000 tons in 1990 to 900,000 tons in 1999 (see FAO, 2003). The most important species group in terms of shelf catches are pelagic fishes, representing about 46% of the catch on average. The second most important species group is clupeoids (about 15%). Cods, hakes and haddocks average about 14%. There were peak catches of capelin in 1992-1993. For more on sardine recruitment, see Valdes and Lavin, 2002. Cyclical oscillations, such as the NAO, have been related to fluctuations in abundance of albacore and bluefin tuna (see Ortiz de Zarate et al, 1997; and Santiago, 1997). Many stocks are either intensively exploited or depleted. There are TAC regulations for anchovy, hake, and blue whiting. General information on fisheries, environmental conditions, human activities, and pollution for the Celtic-Biscay Shelf Large Marine Ecosystem can be found in the OSPAR Quality Status Report. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME.
III. Pollution and Ecosystem Health:
There are ecological disturbances
of target fish species, with alterations in the abundance, distribution and
diversity of fish and marine mammals. Pollution and global change are impacting
different types of coastal habitats (estuaries, coastal lagoons, rocky cliffs,
rocky shores, sandy and muddy shores). For more on the effects of ecosystem
variability and human impact on species and habitats of the Bay of Biscay,
see Valdes and Lavin, 2002. The ecosystem is affected by alterations to the
seabed, the introduction of non-indigenous species, agriculture and sewage
(see Valdes and Lavin, 2002). Introduced species are naturally transported
by currents or are human-induced, caused by an intensification of fisheries
and by travel in ballast water on commercial vessels. The use of DDT in agriculture
has now been banned. There is pressure on the coastal margins from industrial
activities known to cause pollution, such as paper mills, petroleum refineries,
iron and steel works and chemical plants. For more information on industrial
discharges, inorganic and organic compounds, mercury (associated with paper
mill industries), and PAHs (linked to human activities such as marine oil
extraction, industry and oil traffic), see Valdes and Lavin, 2002. Estuaries
and coastal lagoons receive most of the impact of microbiological contamination
of urban origin. In 1992, an oil spill was caused by the supertanker Aegean Sea. The toxic effects of the oil caused a temporal
reduction of the macroinfauna (amphipods, echinoderms, molluscs), with a
simultaneous dramatic increase of opportunist polychaetes. In December 1999,
the supertanker Erika spilled 10,000 tons of oil in shallow
waters off the coast of France. Due to the strong wind in the area, the “black
tide” moved to the coast and large expanses of French beaches were contaminated
by oil. General information on environmental conditions, human activities,
and pollution for the Celtic-Biscay Shelf Large Marine Ecosystem can be found
in the OSPAR Quality
Status Report.
IV. Socioeconomics:
Traditionally the LME has been a region
of intense fishing activity. Whale hunting as an activity began along the
Spanish coast in the Middle Ages. Approximately 5,000 French and Spanish
fishing boats are currently active in the Bay of Biscay. Human activities
in the coastal areas also include aquaculture and farming. Population densities
at the coastal edges of the Celtic-Biscay Shelf Large Marine Ecosystem are
increasing. This fast population growth and socioeconomic development have
resulted in environmental imbalances. Extra pressure was added through tourism,
the new urbanization of coastal areas, transportation and recreational uses
of beaches and shores. General information on human activities and pollution
for the Celtic-Biscay Shelf Large Marine Ecosystem can be found in the OSPAR Quality
Status Report.
V. Governance:
Presently there is limited capacity to plan a sustainable development policy for the coastal areas (see Valdes and Lavin, 2002). The countries situated at the edge of this Large Marine Ecosystem (Ireland, Great Britain, France and Spain) are all members of the European Union. The use of natural marine resources in this LME follow a number of conventions, declarations and regulations, including the European Commission directives and regulations within the Common Fisheries Policies. All in all a large number of instruments from international bodies, such as the United Nations, the International Maritime Organization, and the European Union, exist to conserve natural resources, protect the environment and ensure health and safety standards. The European Community laws protect the environment in terms of air and noise, chemicals and industrial risks, nature conservation, waste and water.
References:
Articles and
LME volumes:
FAO,
2003. Trends in oceanic captures and clustering of large marine ecosystems—2
studies based on the
FAO capture database. FAO fisheries
technical paper 435. 71 pages.
Prescott, J.R.V. 1989.
The political division of large marine ecosystems in the Atlantic Ocean and
some
associated seas. In K. Sherman and L.M. Alexander,
eds. Biomass Yields and Geography of Large Marine Ecosystems. AAAS Selected
Symposium 111. Westview Press, Boulder CO. 395-442.
Valdes, L. and A. Lavin,
2002. Dynamics and human impact in the Bay of Biscay: an ecological
perspective. In K. Sherman and H.R. Skjoldal, eds.
Large Marine Ecosystems of the North Atlantic—Changing states and Sustainability.
Forthcoming volume, Elseviers. 293-320.
Other references:
Atlas of the living resources
of the sea. 1972. Department of Fisheries, Food and Agriculture Organization
of the United Nations (FAO), Rome.
Koutsikopoulos, C. and
B. Le Cann, 1996. Physical processes and hydrological structures related
to the
Bay of Bsicay anchovy. Scientia Marina, 60(2):9-19.
NOAA. 1991. Report of
the ad hoc Committee on Large Marine Ecosystems. NOAA Technical
Memorandum NMFS-F/NEC-92, 19p.
Ortiz de Zarate, V., A.
Lavin and X. Moreno-Ventas, 1997. Is there a relationship between environmental
variables and the surface catch of albacore Thunnus
alalunga (Bonnaterre, 1788) in the North Atlantic? SCRS/97/54.
Report of the Advisory
Committee for Fisheries Management. In ICES Annual Report, 81st Statutory
Meeting. 1993. International Council for the Exploration
of the Sea. Dublin, Ireland.
Santiago, J. 1997. The
North Atlantic Oscillation and recruitment of temperate tunas. SCRS/97/40.