true

ISRA FACTSHEETS

EUROPEAN ATLANTIC

ISRA FACTSHEETS

EUROPEAN ATLANTIC

Bay of Douarnenez ISRA

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Bay of Douarnenez ISRA

Bay of Douarnenez

Summary

Bay of Douarnenez is located in Brittany, northwestern France. This coastal area encompasses the eastern inshore waters of a larger bay that opens in the west to the Atlantic Ocean. The area is influenced by tides and freshwater input from small rivers. The habitat is characterised by sandy substrate, seaweed, kelp, and rocky areas. Within this area there are: reproductive areas (Thornback Skate Raja clavata).

Bay of Douarnenez

Bay of Douarnenez

DESCRIPTION OF HABITAT

Bay of Douarnenez is located in Brittany, northwestern France. This coastal area encompasses the inshore part of a large bay that has a wide opening in the west connecting to the Atlantic Ocean. It is influenced by the tides, with an amplitude of up to ~5 m, and by small freshwater inputs from rivers in the area (Merceron et al. 2007). Currents are low in the area, resulting in eutrophication and there are frequent toxic phytoplankton blooms (Merceron et al. 2007). The habitat is characterised by fine sand substrates, seaweed, kelp, and small rocky areas. The coast has sandy beaches and rocky shores.

This Important Shark and Ray Area is benthic and pelagic and is delineated from inshore and surface waters (0 m) to 20 m based on the bathymetry of the area.

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Bay of Douarnenez is an important reproductive area for one ray species.

A 10-day scientific fishing survey conducted 161 beam trawl fishing operations in this area and the wider bay in March 2017 (Association Pour l’Étude et la Conservation des Sélaciens – APECS unpubl. data 2025). A total of 92 Thornback Skates measuring between 11–90 cm total length (TL) and 78 empty egg cases of this species were caught. The size-at-birth for the species is 10–13 cm TL (Last et al. 2016). Individuals measuring <17 cm TL were conservatively classified as neonate or young-of-the-year (YOY) and comprised a quarter of the catch for the species (n = 24; 26% of total catch). Small skates are scarce in fishing surveys because of the difficulty of catching small individuals. An observer program aboard fishing vessels showed that animals up to 25 cm TL are regularly captured in this area, whereas adults are caught in the wider bay, including outside of this area (APECS 2024). Additionally, the APECS program ‘CapOeRa’ collected skate egg cases on beach surveys along the French coast between 2005–2015 (APECS unpubl. data 2025). Egg cases were identified to species level and counted. Surveys showed that the beaches in this area are a mass stranding site for Thornback Skate egg cases, mainly between November–April. More than 100 Thornback Skate egg cases were regularly collected in this area during each survey, representing a regional hotspot for this species (APECS unpubl. data 2025). Neonate and YOY Thornback Skates and the empty egg cases from the trawl surveys were caught in front of the beaches where stranded egg cases are also found. Combined, these data highlight that this area is important for egg laying, hatching, and the early life stages of Thornback Skates.

Bay of Douarnenez

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