Abstract
The company Parc du Banc de Guérande (PBG) is leading the “Saint-Nazaire Offshore Wind Park” project, which consists of the installation and operation of 80 installed wind turbines with a total power of 480 MW for a production equivalent to 20% of the electricity consumption of Loire-Atlantique. Located between the Houat-Hoëdic archipelago and the island of Noirmoutier, 12km south of the Croisic peninsula, the site covers 78 km².
Among the species which frequent the surroundings of the project implementation area, the Balearic Shearwater Puffinus mauretanicus, endemic to the Balearic Islands where it nests on a reduced number of sites, has a small population in decline (from 2,000 to 4,500 pairs and 19,000 individuals) and is considered, as such, critically endangered (BirdLife International 2018). With almost 20% of the global population which may be stationed in the extended study area of the project during its migratory passage (Fortin et al, 2014), the Balearic Shearwater thus appears as one of the two species of seabirds possibly most affected by the implementation of the Saint-Nazaire offshore wind farm.
Among the suspected impacts, the barrier effect of wind turbines and that of disturbance by navigation, and in particular pleasure boating, are those which appear the most probable (Fortin et al, 2014). The first is characterized by the disruption of migratory or local movements of birds which would avoid the wind farm. The second would cause a movement of feeding or parked birds, all the more impactful if it is frequent. These effects would cause a change in the distribution of birds at sea and lead to an increase in their energy expenditure, a reduction in their food intake and the disruption of their rest during a critical period: that of the postnuptial molt (July-September) . The reception conditions of the migratory stopover could therefore be degraded.
This is why the species is the subject of reduction measure no. 9 (MR9), the general objective of which is to improve the reception conditions of the migratory stopover of the Balearic Shearwater. The details of the actions constituting these operational axes, as well as the deadlines defined for carrying them out, are included in the operational calendar (Table 1).
As described in the MR9 framework document (Sadoul, 2021.), the expanded perimeter of the MR9 covers in its entirety that of the ornithological monitoring at sea carried out since 2013 as part of the environmental diagnosis for the offshore wind farm project of Saint -Nazaire, objective documents of the ZPS of the Loire Estuary - Bay of Bourgneuf and Mor Braz, of the Cormor program and is extended, to the east, to the Bay of Bourgneuf and to the northern part of the monitoring implemented for the YeuNoirmoutier offshore wind farm (Figure 1).
The MR9 is structured around 4 main axes:
- Reducing disruption by wind farm maintenance vessels
- Raising awareness among the general public
- Targeted awareness raising: boating professionals and environmental police services
- Evaluation of the impact of the measure
- Consultation with institutional partners