Site details

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5 stars - Fully protected as a national park or Natura 2000 site by national legislation
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The Gravelines area. Photo: SMW

Synoptic description of site:

Site belonging to the muddy fine sand community with Abra alba. 160 species, mean density of macrobenthos about 4000/m2. Mean biomass (AFDW): 200 g/m2

Extensive description of site:

The Gravelines area belongs to the southern part of the Abra alba community of the North Sea. It is under the influence of waters coming from the Eastern Channel or from the Scheldt estuary, depending on wind conditions. A long-term survey has been performed at this site since 1973

Habitats present:
Seagrass beds 

Description of fauna and flora:

The benthic macrofauna is well documented, related to the Abra alba community. There are 160 species, with a mean mean density of 4000.m-2 and a mean biomass (AFDW) of 200g.m-2.

Human impact:

The area is located far enough from the harbours of Calais and Dunkirk to be only subjected to moderate levels of pollution. The outflow of the Aa river (mean 6 m3.sec-1) has little effect on the benthic communities. This site is studied as the out-of-impact reference area for the nuclear power station of Gravelines.


All facilities for marine biodiversity research are available : research vessels, scientific divers, fully equipped laboratories and accommodation at the Marine Station of Wimereux.

Available database and website:

The global species inventory ("Faune et Flore du littoral du Pas de Calais et de la Manche Orientale") is currently updated It is available as hard copy and will be soon available on-line on the website of the Marine Station. The Gravelines series is available both as an Excel file and in the North Sea Benthos Project database.

Commitment and ongoing research:

The Marine Station, the "Unite Mixte de Recherche ELICO" from CNRS and the Lille 1 University are all based in Wimereux and undertake biodiversity-related research in the area.

Additional Information:

Some references: Prygiel J., Davoult D., Dewarumez J.-M., Glaçon R. & A. Richard, 1988. Description et richesse des peuplements benthiques du littoral français de la Mer du Nord. C.R. Acad. Sci. Paris, 306 : 5-10. Dewarumez J.-M., Davoult D., Sanvicente Anorve L.E. & S. Frontier, 1992. Is the « muddy heterogeneous sediment community » an ecotone between the « pebbles community » and the « Abra alba community » in the Southern Bight of the North Sea . Neth. J. Sea Res., 30 : 229-238. Davoult D., Dewarumez J.-M. & S. Frontier, 1993. Long term changes (1979-1990) in three benthic communities (English Channel): use of factor analysis and rank frequency diagrams for studying structural development. Neth.J. Aquat. Ecol., 27 : 415-426. Carpentier P., Dewarumez J.-M. & A. Lepretre. 1997 Long term variability of the Abra alba community in the Southern Bight of the North Sea . Oceanol. Acta, 20 : 283-290. Fromentin J.-M., Ibanez F., Dauvin J.-C., Dewarumez J.-M. & B. Elkaim. 1997 Long-term variability of macrobenthic communities of the North-west french coast. J. Mar. Biol. Ass. U.K., 77 : 287-310 Ghertsos K., Luczak C., Dewarumez J.-M. & J.-C. Dauvin, 2000. Influence of spatial scale of observation on temporal changes in biodiversity and trophic structures of fine sand communities from the English Channel and the southern North Sea. ICES J. mar. Sci., sous presse.