Proposer: Marine Biology Station – Museum National d’Histoire Naturelle - Concarneau – France.

Name: Yves LE GAL

e-mail address:

Proposed Primary Site:

Glenan Archipelago and Concarneau Bay

Location : South Britanny – France – 10 miles South off Concarneau

The Glenan archipelago is constituted by a series of rocky granite islands covering approximatively 50 Km2 surrounding sandy zones. This "Lagoon"-like structure is unique on the Atlantic coast. It is part of the series of islands of the so-called Armorican pre-continent. This primary site is facing a coastal system of rias and short estuaires (tidal systems).

PRISTINESS: Primary sites should be as free as possible from anthropogenic stressors, and natural stressors atypical of the region (e.g. reduced salinity, high turbidity).

List potential sources of pollution that are likely to impinge on the site:-

Industrial pollution: None

Agricultural pollution: None

Mining: None

Dumping: None

Dredging: Locally (maërl beds)



What is the human population of the site in total and per unit area? What is the average population growth per year?

The archipelago is practically devoid of permanent inhabitant (in any case the number is below 5-10). Construction is stricly restricted and no population growth will occur. However, during the summer period there is a relatively important tourist activity (see below).


How is sewage disposed of? If possible give an estimate of the quantity and quality of the output.

Solid garbages are sorted out and periodically sent back by th way of a special barge to the continent for upgrading.

Due to the shortage of freshwater in the islands toilet sewage is of a "dry toilet" type. liquid effluents are sent back to the continent at the end of tourist season.

Most of the energy is obtained from renewable forms : photo cells, wind mills. This programme has been carried out by the commune of Fouesnant within the framework of the LIFE Programme (Sustainable tourism). As a consequence there is practically no output in the sea.




Describe the extent of commercial fishing in the area. Please specify the kinds of gear used (trawling, seine netting, lobster pots etc.)

Commercial fishing is diverses in a rea around isles of Glenan where only small boats (<12 m) can operate and trawling is prohibited. These activities can be classified in 5 kinds according to target species.

- Purseine : 8 boats are working throughout the year : target species are blue fishes (Sardina pilchardus, Scomber scombrus, Engraulis encrasicolus, Sprattu sprattus).

- Net : targets species , hake (Merlucius merlucius), pollack Pollachius pollachius), whiting (Merlangius merlangius), dover sole (Solea solea).

- Hand line and longline : targets species , bass (Dicentrachus labrax).

- Crustacean pots : the most important species are Spider crab, lobster and shrimp.

- Dregde for shell : the most important species are scallop during the winter (Tapes and Spisula; A seasonal activity concerns sea urchins.


Give an account of tourist activities in the area (how many tourists per year; what do they do?).

During spring-summer period 2 islands welcome a sailing school (average /week). Free sailing is rather important in july, august (average 50-60 boats per day with a peak (up to 150 during week ends). Promenade boats are allowed to land only on one island (St-Nicolas) : Peak frequentation : 1500 – 2000 individuals during july-august on the archipelago.



Provide evidence that there are no natural stressors such as high turbidity or reduced salinity that are atypical of the region.

Waters in the Glenan archipelago are particularly clear, due mainly to the lagoon-like structure and the absence of important estuary around. For the same last reason, temperature range is typically 6-8° (February, 15-18° (September). salinity is quite constant.


Give references to any chemical or physical data that support the claim that this is a pristine site.

As far as chemical and physical data are concerned, the area is under permanent survey by RNO (Reseau National d’Observation – national Network of survey) since 1998 (Point : Mousterlin). The data collected are clearly demonstrating the cleanless of the waters (see : ) The area is also under permanent survey for bacteria and for toxic planctonic blooms (Ifremer networks).


HABITATS: The site should comprise a mosaic of habitats in a well-defined area that are representative of the region.

The archipelago presents a very diversified panel of facies in the laminarian biocenosis. This is a consequence of the lagoon-like structure of the islands : all the grades in the scale of water agitation can be found. Another consequence is the complex mosaïc of sedimentary and rocky bottoms. The junctions of these different systems : laminarians, maërl, zostera , etc are particularly rich.

As far as the rocky global biomass is concerned, the Glenan zone is less rich than some areas of the North coast of Britanny but richer than the sector of Brest-Iroise. This difference is mainly linked to algal population.

In addition , the archipelago comprises several remarkable populations : Pollicipes cornucopiaie, Paracentrotus lividus, bushes of Holidrys siliquosa.

Very dense laminarian foests (Sacchoriza bulbosa, Laminaria hyperborea) concentrations of Cystoseita.

At a biogeographical point of view the glenan archipelago is situated at the northern limit of meridionnal and at the southern limit of septentrional influences. This results in a unique mixing of many species and biota.


List the range of habitats present at the site:-


Rock: Very exposed to sheltered

Sand: Beaches exposed to sheltered



Rock: Bed rocks, vertical cliffs, overhangs


Mud: Locally

Seagrass beds: Yes

Maerl beds




How representative is this site of its region (i.e. what regional habitats are missing)?

BACKGROUND INFORMATION: The site should already be well-studied (i.e. biodiversity studies should not rely entirely on new research).

The Glenan site has been studied reguarly for more than 120 years (see annex for publications relative to inventories).

For what groups of organisms are comprehensive inventories available? Please list major taxa in each category below, and list publications.

Macrobenthos: Sponges, hydrozoa, bryozoa, anthozoa, ascidians

Meiobenthos: -

Microbenthos: -

Zooplankton: -

Phytobenthos: Algae

Phytoplankton:Permanent survey (Rephy) by Ifremer.


List any other publications relating specifically to the biodiversity or environment at the site.



List publications relating to historical/time-series data at the site.



Is biodiversity information available in electronic form? If so, what is the nature of the database (CD-ROM, web-site)?




PROTECTION STATUS: The pristine nature of the site should be protected by legislation if it is to be a "flagship site" for future monitoring.



The whole archipelago is a classified site (protection of nature and patrimony). The St-Nicolas island comprises also a botanical reserve.

The marine environment of the Archipelago comprises several zones classified ZNIEFF (zones naturelles d’intérêt faunistique et floristique). It is also included as zone FR 53 000 23 in the programme Natura 2000. Fish trawling and scuba fishing is forbidden. Other fishing practices (scallops, Haliotis, sea urchins, stricky regulated).







What conservation legislation (national, European, international) is currently in place, how well is it implemented and how long will it last?





FACILITIES: The infrastructure for biodiversity research should be available. There should also be a national commitment in terms of financing and scientific activity (i.e funding should not be entirely dependent on the success of any future EU programme).




How accessible is the location?

Is it limited seasonally (e.g. not accessible in winter)? NO

Is it accessible by car or by boat (indicate means of transport and distance from laboratory facilities in km)?

10 miles from Concarneau. Regular service in spring-summer.


What is the status of local facilities:-

Laboratory: Marine Biology Station. Museum National d’Histoire Naturelle -

Boats: 1 (8.50 m) All collection facilities.

Are these facilities available for guest researchers? Yes


What facilities are there for SCUBA diving? SCUBA facilities in Concarneau and on St-Nicolas Island



What housing is available? In relation with sailing and diving clubs. Municipal housing.

List the sources of funding currently in place specifically for biodiversity research at this site (from where and how much).

Mainly Ministry of Environment and Regions of Britanny.

List by name the persons currently involved in biodiversity research at this site, their roles and the percentage of their time spent on this research.

- Claude BEAUPOIL 50 %

- Annie CASTRIC 50 %

- Sandrine COURTEL 50 %

- Pierre NOEL 20 %

- Thomas BARTOLOMAEUS 10 %

In addition staff and members of the Associations for the Discovery of the Sub-marine World (150 members biologist divers).



The coast and the estuary system facing the Glenan archipelago is proposed as a satelite site (100 km from Penmarch to Quiberon).

The main characteristics of this coast is the presence of a series of estuaries corresponding to short (a few kms) or medium length 20 to 50 km rivers. These estuaries are strongly affected by the tides. As a whole the system is a major component of the productivity in the surrounding (particularly fish nurseries).

Several of these estuaries have been studied for 2 or 3 decades. one of them (Laïta) was strongly polluted (paper mill, agrofood) and is still under recovery and constitute a paradigm for the follow up of this type of process.



Please use this section to add any additional supporting comments, for example what do you think is special about your site from the biodiversity point of view, why is it important to monitor biodiversity there, and what is the public awareness of this?


This site can be considered as a hot spot for marine biodiversity in east-north Atlantic waters and as really pristine from chemical and physical pollution. It is relatively far from the continent as well as classical cargos roads.

Important measures of for the protection of the environment have been taken in due time. It concerns tourist behaviour as well as commercial fishing practices.

The presence of the centuries old Marine Station at Concarneau, linked to the National Museum of Natural History garantees the conservation of archives as well as the follow up of ecological surveys. This is completed by existent collaboration with the University of Western Britanny (80 km) and growing collaborations with the universities of Bielefeld and Göttingen.









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ADMS, 1995. Inventaire de la faune et de la flore sur les fonds rocheux autour de l’ile d’Ouessant. Rapport Convention ZNIEFF 94, Direction régionale de l’Environnement, Rennes. 109p.

ADMS, 1996. Inventaire de la faune et de la flore sur les fonds rocheux sublittoraux en Proche Iroise et Rade de Brest. Rapport Convention ZNIEFF 94, Direction régionale de l’Environnement, Rennes. 166p.

AUGRIS, C., BLANCHARD, M. & P. BERTHOU. 1986. Etude d’un site d’exploitation de maërl au nord des Iles de Glenan. Rapport IFREMER, DERO, 86p + 7 cartes.

BILLARD, A. 1922. Note sur une espèce nouvelle des côtes de France, Dynamena dubia. Bull. Soc. zool. France, 47 : 344-348.

BILLARD, A. 1923. Note sur quelques hydroïdes des côtes de France, Ibid., 48 : 13-20.

BOURON, D. & M. GLEMAREC. 1972. Bionomie de l’archipel de Glénan. in Rapport CNEXO 71/ 363.

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LAFARGUE, F. 1968. Les peuplements sessiles de l’Archipel de Glenan. Les Didemnidae. Systématique et écologie. Vie Milieu, 19 (2A) : 353-446.

LAFARGUE, F. 1969. Les peuplements sessiles de l’archipel de Glenan. Inventaire Anthozoaires. Vie Milieu, 20 (2B) : 415-436.

LAFARGUE, F. 1970. Les peuplements sessiles de l’archipel de Glenan. Inventaire Ascidies. Vie Milieu, 21 (3B):729-742.

LAFARGUE, F. 1987. The Didemnid Ascidian Fauna of France. Ann. Inst. océanogr. 63 (1) : 1-46.

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L’HARDY-HALOS, M.TH., 1973. Observations sur deux Delesseriacées (Rhodophycées, Céramiales) des côtes de Bretagne : le Nitophyllum heterocarpum (Chauvin) Ernst & Feldmann et le Radicilingua thysanorhizans (Holmes) Papenfuss. Bull. Soc. Phycol. de France , 18 : 33-46.

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Se reporter également aux ouvrages suivants, donnant , en plus de la liste des espèces, des indications sur leur biotope :

- Inventaires de la Flore et de la Faune marine de Roscoff (IFMR):

Spongiaires . 1969. Editions de la Station Biologique de Roscoff.

Algues: Trav. Stat. biol. Roscoff, 1954 , 5 + additions , 1964, 15

Cnidaires: «  «  «  1965, 16

Bryoz. Echinod. Brachiop. «  1951, 2 , suppl. 4

Mollusques: «  «  «  1952, 3

Annelides: «  «  «  1967, 17

Tuniciers: «  «  «  1955, 6

- Inventaires de la faune sessile de l’archipel de Glenan:

Spongiaires : Vie et Milieu, 1969, 20 (1B) : 177 - 209

Hydraires: «  «  1969, 20 (2B) : 387 - 414

Anthozoaires: «  «  1969, 20 (2B) : 415 - 436

Bryozoaires: «  «  1971, 22 (1B) : 193 - 225

Ascidies: «  «  1970, 21 (3B) : 729 - 742

PLYMOUTH MARINE FAUNA, 1957. Marine Biological Association of the U.K., 457p.

Synopses of the british Fauna. Academic Press, London.

n° 1 : Ascidians.

n° 18 : Anthozoans.

n° 14 : Ascophoran Bryozoans.

n° 33 : Ctenostome Bryozoans.

n° 34 : Cyclostome Bryozoans.