Saint-Nazaire Offshore Wind Farm

Wind Project Site

Title: Saint-Nazaire Offshore Wind Farm

Status:

Operating

Project Manager:

EDF Renewable Energy, Enbridge

Turbine Developer:

General Electric Company

Foundation Manufacturer:

Eiffage Métal

Construction Start:

September 1, 2019

Operation Start:

November 1, 2022

Info Last Updated:

March 27, 2026

Contact:

EDF Press Contact
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Website:

External Link

Details

Technology:

Fixed Offshore Wind

Project Scale:

Commercial Farm

Turbine Model:

Haliade 150-6MW

Hub Height:

100 m

Rotor Diameter:

150 m

Number of Turbines:

Capacity per Turbine:

6 MW

Installed Capacity:

480 MW

Support Structure:

Monopile

Inter-Array Cables:

33 kV

Export Cables:

AC, Unburied Seafloor Cables

Export Cable Voltage:

220 kV

Number of Export Cables:

Cable Landfall:

Trenched

Physical Site:

Shallow Water (<60m), Marine, Hard-Bottom Habitat

Water Depth:

12-25 m

Distance from Shore:

12-20 km

Country:

France

Description

The Saint-Nazaire Offshore Wind Farm is the first offshore wind farm in France, developed by EDF Renewables, Enbridge, and GE. The project is the first of three awarded by the French government, with the next wind farms to be developed near Fécamp and Courseulles-sur-Mer. These projects are planned to include a total of 238 wind turbines with a capacity to provide power to 2 million people. These developments are part of France’s goal to reach a target of 32% renewable energy consumption by 2030.

The site on the Banc de Guérande was chosen for its combination of strong winds and relatively shallow depth as well as its relative freedom from maritime constraints and compatibility with environmental issues. The wind farm is also open to navigation if vessels are less than 25 meters in length and follow certain speed, activity, and navigation rules.

The GE Haliade turbines used for the project were first tested at a land-based wind energy installation along the Loire River. After the successful test, a second turbine was deployed off the coast of Belgium for marine testing of the deployment method.

Location

The Saint-Nazaire Offshore Wind Farm covers a 78 km² area of the Banc de Guérande, 12 km to 20 km off the Loire-Atlantique coast. The wind farm is operated and maintained from the port of La Turballe where a 1,250-m² maintenance building is located. There are three maintenance vessels located at La Turballe for daily operations on the wind farm. Cable landfall occurs near Saint-Nazaire and then travels overland through Trignac, Montoir-de-Bretagne, Donges, and ends at Prinquiau.

Project Timeline

November 2022: Fully operational and commissioned
June 2022: First electrical production
April 2022: First turbine installed
August 2021: Offshore substation and 19 wind turbine foundations installed
June 2021: 73 monopile foundations excavated
May 2021: First foundation installed
September 2020: First turbine nacelle manufactured
September 2019: Construction started
June 2019: Final decision from the Conseil d’État awarded
2017: Construction and operating permits issued
2012: Government of France names Éolien Maritime France (EMF) as winning bidder for project
2008: Start of technical and environmental studies

Licensing Information

In 2017, French local authorities issued construction and operating permits. In June 2019, the Conseil d’État delivered a final decision upholding these authorizations.

Key Environmental Issues

Beginning in 2008, several studies provided background environmental information about the proposed installation areas, identified potential environmental issues, and proposed monitoring plans for the site. The project then performed baseline or reference studies in 2019 prior to the beginning of marine operations and construction. The baseline studies were used for during- and post-construction comparisons but also provided comparisons to data from the earlier studies. Following the baseline studies, monitoring has continued each year and is posted in an annual summary report.

Several key environmental issues have required the implementation of monitoring measures: changes in water quality; effects on benthic communities and fisheries (including large crustaceans and fish larvae); impacts to marine mammals, birds, and bats; and potential noise effects on shorelines.

In addition, the wind farm area is used by sensitive species of marine mammals and seabirds; therefore, several mitigation measures were put in place during construction activities, as well as for the whole duration of the project:

During construction activities, pingers and seal-scarers were used before any pile driving started to ward off marine mammals potentially in the vicinity. Hydrophones mounted on buoys around the construction zone allowed to verify in real time the absence of cetaceans before and during pile driving. Once all clear, pile driving started, following a gradual increase in intensity, ready to stop immediately if any marine mammal were detected in proximity to the construction zone. In addition, a bubble curtain was used to limit in-water propagation of pile-driving noise.
To protect and improve the quality of nearby breeding grounds of the Great black-backed gull (Larus marinus), specific measures were implemented to remove rats, that prey on eggs, from islets in the vicinity of the wind farm. In addition, to protect the critically endangered Balearic shearwater (Puffinus mauretanicus) if any were observed in the wind farm area at any time, specific navigation rules were established, as well as outreach to recreational boaters to educate on this very sensitive species.
During the construction phase, it was required that vessels related to the construction activities limit their night-time lighting, as long as it was safe to do so, to decrease the potential attraction effects to birds, bats, and other animals attracted by anthropogenic lights. In addition, safety markers for the wind farm during its operation phase are designed as to decrease night-time light attraction.

Environmental Papers and Reports

Bilan annuel 2024 des études environnementales sur le parc éolien en mer de Saint-Nazaire Parc éolien en mer de Saint-Nazaire 2025
Bilan annuel 2023 des études environnementales sur le parc éolien en mer de Saint-Nazaire Parc éolien en mer de Saint-Nazaire 2024
Parc éolien en mer de Saint Nazaire _ Suivi de l'avifaune et de la mégafaune marine.: Rapport final de la mesure MSU10 en phase de construction (Octobre 2021- Septembre 2022) Biotope 2023
Suivi écologique le long du fuseau: Suivi substrats rocheux et enrochements en 2021: Suivi substrats meubles en 2022 TBM Environnement 2023
Parc Éolien en Mer de Saint-Nazaire Banc de Guérande: Suivi halieutique en phase de construction Hacquebart and Couraud 2023
SAINT-NAZAIRE Bilan environnemental annuel 2022 Parc éolien en mer de Saint-Nazaire 2023
PARC EOLIEN EN MER DE SAINTNAZAIRE: Phase Construction – Rapport opérationnel Bellanger et al. 2022
SUIVI DE LA QUALITE DE L’EAU, DES HABITATS ET PEUPLEMENTS BENTHIQUES: PARC EOLIEN EN MER DE SAINT-NAZAIRE PHASE CONSTRUCTION 2022 Tertre 2022
RAPPORT D’ACTIVITÉ MR9 Année N+1 MAZIERE 2022
RAPPORT D’ACTIVITÉ MR10 ANNÉE N+2 MAZIERE et al. 2022
Suivi par acoustique passive du bruit ambiant et de la fréquentation des mammifères marins dans le cadre de la construction du parc éolien en mer de SaintNazaire: Phase de construction : Mesure de Suivi N°8 Chompret et al. 2022
Bilan annuel 2021 des études environnementales sur le parc éolien en mer de Saint-Nazaire Parc éolien en mer de Saint-Nazaire 2021
Document cadre de la MR9 Réduire les dérangements de la halte migratoire du Puffin des Baléares Sadoul 2021
RAPPORT D’ACTIVITÉ MR10 ANNÉE N+1 MAZIERE et al. 2021
Parc éolien en mer de Saint-Nazaire – Suivi de l’avifaune et de la mégafaune marine: Société Parc du Banc de Guérande Octobre 2020 Biotope 2020
Suivi acoustique passif du bruit ambiant et des mammifères marins dans le cadre du parc éolien en mer de Saint-Nazaire Chompret et al. 2020
SAINT-NAZAIRE Bilan environnemental annuel 2020 Parc éolien en mer de Saint-Nazaire 2020
Parc Éolien en Mer de Saint Nazaire Banc de Guérande: Étude de l’état de référence halieutique SINAY - Maritime Data Solutions 2020
Document cadre de la MR10 Soutien à la mise en œuvre d’actions de préservation des îlots utilisés comme site de nidification, en particulier pour le Goéland marin Le Guen and Leicher 2019
Parc éolien en mer de St Nazaire : Analyse complémentaire des impacts sur le Goéland marin (Larus marinus) McGregor 2014
Diagnostic environnemental 2013-2014 pour le groupe avifaune et évaluation du risque d’impact dans le cadre du projet de parc éolien en mer de Saint- Nazaire. Matthieu et al. 2014
Projet de Parc éolien en Mer de Saint- Nazaire. Diagnostic « chauves-souris » Etienne and Matthieu 2014
Etude d’Impact Acoustique du Parc Eolien Offshore du Banc de Guérande, Saint-Nazaire, France Clorennec and Folegot 2014
Projet de parc éolien en mer de Saint-Nazaire -Banc de Guérande – Etat initial, effets, impacts et mesures Parc éolien en mer de Saint-Nazaire 2014
Parc Eolien en Mer de Saint Nazaire Etude d’impact environnemental Halieutique 2014

Environmental Monitoring: Saint-Nazaire Offshore Wind Farm

Phase

Stressor

Receptor

Searches description, design and methods, and results.

ID	Phase	Stressor & Receptor	Design and Methods	Results	Publications	Data
2131462	Baseline	Bats	Passive Acoustic Monitoring Bat echolocation calls were recorded using fixed coastal monitoring stations and mobile recording units positioned along migratory pathways. Acoustic data was analyzed to identify species presence, abundance, and activity patterns in relation to construction timelines and locations.	Complete Species-specific vulnerability to disturbance was observed, with near-threatened migratory bat species showing heightened sensitivity. Analysis revealed varying degrees of spatial-temporal overlap between migration corridors and construction activities, identifying populations requiring targeted conservation measures.	Etienne and Matthieu 2014	No data available
2131463	Baseline	Birds	Boat Observer Study Marine bird surveys were conducted via vessel-based observations in 2013 and 2019. Species identification, distribution patterns, and temporal activity were documented. Potential wind farm impacts were assessed through spatial analysis of species occurrence relative to planned development areas.	Complete Impact assessments were predominantly medium for most observed species. Two species exhibited elevated vulnerability: Balearic shearwater (Puffinus mauretanicus) and Great black-backed gulls (Larus marinus) were classified as subject to strong potential impacts. Comparative analysis between the 2013 and 2019 surveys demonstrated consistent findings regarding species distribution and projected impact levels. 2013 and 2019 surveys demonstrated consistency in findings across temporal sampling periods.	Matthieu et al. 2014	No data available
2131464	Baseline	Fish, Invertebrates	Marine Resource Assessment Research conducted in 2013 and 2019 consisted of: (1) Literature review to identify potential species presence and vulnerability zones; (2) Field sampling of adult marine organisms using traps, nets, and longlines; (3) Collection of hydrological parameters concurrent with biological sampling; (4) Spatial and seasonal distribution analysis of captured species; (5) Development of baseline resource assessments, impact mitigation recommendations, and monitoring protocols.	Complete Site assessment determined the area does not function as a significant nursery or spawning ground, though it serves as juvenile development habitat. Impact analysis identified foundation construction and cable installation as activities with highest potential ecological effects, though overall impact was classified as minor. Findings recommend implementation of a "soft start" approach to construction activities to evaluate actual ecological responses before full-scale development.	Halieutique 2014	No data available
2131461	Baseline	Invertebrates, Physical Environment	Benthic Habitat Video Survey Baseline benthic ecosystem assessment conducted in 2013 and 2019 at proposed development and reference sites using underwater video transects, sediment/rock sampling, and diver surveys. Analysis included sediment granulometry, organic content, species metrics, and habitat classification to develop impact assessments, mitigation strategies, and monitoring protocols.	Complete Assessment determined permanent habitat alteration would be negligible to minimal relative to the total wind farm area. Localized substrate modifications at infrastructure points represent a small fraction of available benthic habitat, indicating limited ecological significance of anticipated changes.	Le Guen and Leicher 2019	No data available
2131460	Baseline	Marine Mammals	Passive Acoustic Monitoring Marine mammal presence and activity patterns were assessed using a network of acoustic monitoring devices. Fixed acoustic recorders were deployed at wind farm perimeter corners, supplemented by six mobile C-PODs (Cetacean-Porpoise Detectors) that were repositioned across two designated survey zones. Acoustic data were analyzed to determine species occurrence, relative abundance, and spatial distribution patterns.	Complete Acoustic detections confirmed regular presence of three cetacean species: common dolphin, bottlenose dolphin, and harbour porpoise throughout the study area. Spatial analysis of detection patterns revealed no evidence of critical habitat within the wind farm footprint. Distribution appeared relatively uniform without identifiable hotspots of activity, suggesting the absence of key feeding, breeding, or transit areas for marine mammals within the development zone.	Biotope 2020	No data available
2131465	Baseline	Physical Environment	Acoustic Field Survey Baseline benthic ecosystem assessment conducted in 2013 and 2019 at proposed development and reference sites using underwater video transects, sediment/rock sampling, and diver surveys. Analysis included sediment granulometry, organic content, species metrics, and habitat classification to develop impact assessments, mitigation strategies, and monitoring protocols.	Complete Assessment determined permanent habitat alteration would be negligible to minimal relative to the total wind farm area. Localized substrate modifications at infrastructure points represent a small fraction of available benthic habitat, indicating limited ecological significance of anticipated changes.	Clorennec and Folegot 2014	No data available
2131459	Construction	Displacement Bats, Birds, Marine Mammals	Visual Survey An opportunistic megafauna survey was conducted during and after construction to assess habitat use changes. Visual surveys from construction vessels and volunteer boaters recorded marine mammals, birds, and bats.	Complete Marine mammals were observed in the area at least once a week during summer 2021, and less often in the fall.	Parc éolien en mer de Saint-Nazaire 2021	No data available
2131447	Construction	Displacement, Attraction, Habitat Change, Lighting Birds, Marine Mammals	Boat and aerial bird surveys During the construction period, 4 boat surveys and 8 plane surveys were conducted. Boat surveys included 10 transects within the wind farm area with real-time bird observations recorded. Plane surveys covered 10 transects in the broader vicinity of the wind farm and through its center, utilizing 4 downward-facing cameras for later data processing.	Complete The surveys revealed that certain bird species avoided the wind farm area during construction, likely due to the absence of fishing boats as food sources, while others were attracted to the new structures for roosting. However, the majority of bird species showed no significant impacts. Regarding marine mammals, harbor porpoises were displaced from the wind farm area during construction, whereas dolphins appeared unaffected.	Biotope 2023	No data available
2131446	Construction	Displacement, Habitat Change Fish, Invertebrates	Ichthyoplankton and Fish Diversity Survey The ichthyoplankton survey collected eggs and larvae monthly at five stations (three within the wind farm, two outside) for five months using paired Bongo zooplankton nets. The fish and crustacean survey employed pots and gillnets for crustaceans and longlines for demersal fish across five surveys at six wind farm stations and four outside stations.	Complete The ichthyoplankton survey revealed no construction-related impacts on species richness, diversity, or evenness from egg data; larval data showed no impacts on diversity or evenness but differences in species richness compared to baseline. Fish and crustacean surveys detected no impacts on diversity indices or CPUE from gillnet and longline data. Changes to assemblage composition and lobster size were observed from pot data, though sampling bias may have influenced these findings.	Hacquebart and Couraud 2023	No data available
2131448	Construction	Habitat Change Invertebrates	Benthic Surveys Benthic surveys of soft bottom and rocky habitats were conducted post-construction along the cable route. Infauna were sampled at 8 stations along the cable route and 8 outside it using a Day grab and Rallier du Baty dredge, with 5 replicates per station. Scuba divers collected encrusting fauna and flora on rocky substrates at 2 stations using scrapers and vacuums, accompanied by quadrat photos taken before scraping. Surveys at concrete mattresses involved photographing 15 0.1-m² quadrats at 2 stations and conducting 10 scuba transects to assess large invertebrates and kelp along mattress surfaces.	Complete No significant changes in infauna assemblages or ecological indices were observed, except at one station. Annual variations in encrusting assemblages were detected, though they were not linked to construction activities. Eight months post-construction, colonization of the concrete mattresses was evident, with 103 different taxa observed.	TBM Environnement 2023	No data available
2131456	Construction	Habitat Change Invertebrates	Benthic Surveys Benthic surveys assessed sediment composition and habitats in soft-bottom areas around the wind farm using a Van Veen grab and a Ralier du Baty dredge. Samples were subsampled for various analyses after collection.	Complete Sediment composition down current from the wind farm showed some changes between baseline and construction, which may or not be linked to the accumulation of drill cuttings after pile driving. There were no significant differences observed in benthic assemblages.	Tertre 2022	No data available
2131457	Construction	Noise Marine Mammals	Passive Acoustic Monitoring Six floating hydrophone systems (Smart-PAM) were strategically positioned surrounding the construction site to detect marine mammal vocalizations. Acoustic data was transmitted and analyzed in real time to enable mitigation through work stoppages when protected species were detected in proximity to active pile driving operations. Monitoring occurred both before and during pile driving activities to establish presence of sensitive species.	Complete The acoustic monitoring system detected delphinid vocalizations on 11 separate occasions during construction operations. These detections occurred across 7 distinct pile-driving events, triggering 8 temporary work stoppages in accordance with mitigation protocols. Real-time detection and response demonstrated successful implementation of acoustic monitoring as a construction mitigation measure.	Sadoul 2021	No data available
2131454	Construction	Noise Marine Mammals, Physical Environment	Acoustic Survey Ambient noise and pile driving noise propagation were measured near the wind farm to assess impacts on marine mammals. Bottom-mounted hydrophones were deployed three times at four locations for 30 days, and floating hydrophones were used around turbines during pile driving activities.	Complete Results show that pile-driving noises were detectable 20-34 km away from the source, but vessel and drilling noises were perceivable at much shorter distances. Vocalizations from 4 marine mammal species were regularly recorded during the surveys; their presence and behavior in the surveyed area did not change from the baseline data.	Chompret et al. 2022	No data available
2131445	Construction	Habitat Change Physical Environment	Water Quality Survey Water quality changes during construction were monitored at fish survey stations using a multisensor sonde, measuring water temperature, salinity, turbidity, fluorescence, and dissolved oxygen in vertical profiles.	Complete None of the parameters measured show results different from the natural variability, nor differences with the baseline data.	Hacquebart and Couraud 2023	No data available
2131450	Construction	Habitat Change Physical Environment	Water Quality Survey A Niskin bottle was used to collect subsurface and bottom water samples at the same 7 stations, to measure physicochemical parameters, biological elements and nutrients, and toxicity of samples.	Complete No noticeable changes in water quality were measured, except greater oxygen concentrations and lower nitrate concentrations after construction.	TBM Environnement 2023	No data available
2131455	Construction	Habitat Change Physical Environment	Water Quality Survey Phytoplankton and water quality changes were measured near the wind farm using a multisensor sonde for vertical profiles of depth, temperature, turbidity, salinity, and dissolved oxygen, and a Niskin bottle for mid-depth chlorophyll and suspended matter samples.	Complete Results were relevant to the known seasonal variability in the area and did not show any impacts from construction activities.	Tertre 2022	No data available
2131458	Construction	Habitat Change Physical Environment	ROV Video Survey Rocky habitats were qualitatively monitored during construction due to safety constraints. Video observations with a remotely operated vehicle (ROV) assessed impacts around four turbine foundations, including vessel footprints, drill cuttings, and scour protection.	Complete The videos provided visual observations of the physical habitat right after construction.	Parc éolien en mer de Saint-Nazaire 2021	No data available
2131444	Operations	Displacement Bats	Acoustic surveys Bat activity was recorded using acoustic devices (Batloggers) deployed from August to October 2023. Additional devices were placed at control locations to provide comparative data. Recordings captured nightly presence and activity density to assess visitation levels across the study period. Environmental variables, including temperature, wind speed, humidity, and timing of bat detections, were considered to evaluate factors influencing bat activity at both sites.	Complete Activity levels were similar at both locations, with peaks primarily in September and October, dominated by the Nyctaloides group, especially Leisler's bat. Factors influencing activity included temperature (~20.5°C), low wind speeds (1–2 m/s), southerly winds, and humidity below 70%. The difference in nightly arrival times between sites suggests an influence from the proximity of Hoëdic Island. While migratory behavior remains uncertain, seasonal transit and local exploration for food or dispersal are likely contributors to bat presence.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131453	Operations	Displacement Bats	Acoustic Sensor Bat Monitoring Bat activity was monitored from Fall 2022 to Fall 2023 using Batloggers installed at three wind turbines, and at a control site. Monitoring focused on species diversity, activity density, and factors influencing bat behavior.	Ongoing Bat activity was low overall but peaked from September to October at both the G02 turbine and control site, with Leisler's bat being the most frequently detected species. Migratory behavior was uncertain, with bats potentially venturing offshore for food or dispersal. Activity was influenced by temperatures above 20.5°C, low wind speeds (1–2 m/s), southerly winds, and humidity below 70%. Earlier activity at the lighthouse was likely due to proximity to Hoëdic Island. Monitoring continued efficiently in 2024, with data analysis ongoing.	Parc éolien en mer de Saint-Nazaire 2023	No data available
2131443	Operations	Displacement, Attraction, Avoidance, Habitat Change, Lighting Birds	Boat and Aerial Bird Surveys Bird monitoring during the operational phase focuses on tracking distribution, densities, and spatio-temporal changes across the wind park and extended study area. Large transects are carried out via aircraft with video acquisition, while short transects are conducted via boat with onboard observers. Surveys target key biological periods, including wintering, migration, breeding, and post-breeding dispersal.	Ongoing Data collected during the first year of operation (October 2023–September 2024) is being processed and interpreted. Analysis methods were validated in a scientific meeting in September 2024, ensuring robust evaluation of bird distribution, impact correlations, and the effectiveness of mitigation measures.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131441	Operations	Habitat Change Fish	Fish & Ichthyoplankton Comprehensive Assessment Multiple survey methods targeting different fish life stages and habitats: (1) Ichthyoplankton surveys using Bongo paired zooplankton nets at five stations; (2) Fish net surveys using gillnets for demersal species; (3) Longline fishing targeting commercial species. Stations located both within and outside the wind farm area.	Complete Ichthyoplankton: No major difference in fish egg biodiversity between baseline and operation. Fish larvae showed lower species richness in 2023, but differences appear unrelated to wind farm presence. No apparent impact on spawning function for resident species. Fish Net Surveys: Overall abundance decreased in 2023, with species diversity and evenness showing little change. Longline Fishing: No difference in diversity indices between baseline and operation phases. Overall Assessment: Multivariate analyses across all methods indicate observed differences in fish populations primarily associated with temporal variation in environmental parameters rather than wind farm operation effects.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131440	Operations	Habitat Change Invertebrates	Benthic Sampling and Crustacean Surveys Benthic surveys assessed multiple habitat types using: (1) soft sediment sampling with Van Veen grab and Ralier du Baty dredge for infauna and epifauna collection, and (2) rocky habitat and structure colonization assessment via scuba diver transects along rocky areas, cables, and turbine foundations. Pot sampling targets crustaceans of commercial interest, with surveys conducted at stations within and outside the wind farm.	Complete Findings align with previous research indicating wind farm effects on invertebrates are temporary, localized, and primarily limited to construction phases.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131451	Operations	Habitat Change Invertebrates	Trap Surveys Crustacean trap surveys were conducted during the operational phase to monitor abundances and diversity indices compared to baseline data, with a focus on species composition. Sampling included targeted collection of Brown Crab and comparison across varying habitats and physicochemical conditions. Efforts included tagging and recapture efforts to study European lobster populations and fisheries, although tagging was limited in 2023 and paused in 2024.	Complete Trap surveys showed reduced abundances during monitoring, except for a high Brown Crab sample in July 2023. Diversity indices remained unchanged, but species composition shifted, with Spider Crab absent during monitoring and European Lobster and Brown Crab dominating. Differences were linked to physicochemical factors and sampling biases. The Lobster Program reported one recapture in 2024, prompting a redirection of objectives to address declining lobster catches and support population recovery.	Parc éolien en mer de Saint-Nazaire 2023	No data available
2131442	Operations	Noise, Displacement, Attraction, Avoidance Marine Mammals	Combined Acoustic Monitoring & Opportunistic Observations Comprehensive marine mammal monitoring was performed using: (1) Bottom-mounted hydrophones at multiple stations around wind farm and control sites; (2) Trained maintenance vessel crews documenting opportunistic sightings. Winter and summer monitoring periods implemented.	Ongoing Operational wind farm noise (10-250 Hz range) was found only audible to low-frequency cetaceans at closest monitoring station. Dolphin presence was consistent with pre-construction baseline (occasional to frequent within park, daily in Mor Braz), with 29-43% of encounters showing potential foraging behavior. Porpoise detections were limited to specific locations and classified as occasional to exceptional. No significant displacement effects were observed. Ambient noise levels were slightly lower than baseline period, with prominent benthic fauna sounds in rocky habitat areas. Overall analysis suggests marine mammal activity patterns remain consistent with pre-wind farm conditions.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131452	Operations	Displacement, Noise Marine Mammals	Noise Monitoring Marine mammal activity and ambient noise were monitored during the wind farm’s operational phase using passive acoustics. Data were collected at multiple stations covering the wind farm area and the nearby Mor Braz region, with seasonal monitoring conducted in summer and winter. The monitoring targeted both ambient noise sources and acoustic activity of marine mammals like dolphins and porpoises.	Ongoing The wind farm generated noise in the 10–250 Hz range, audible only to low-frequency cetaceans near the turbines. Dolphin acoustic activity was recorded across all stations, with presence ranging from occasional to frequent, and daily activity noted in the Mor Braz. Dolphin activity included potential foraging (29–43% of events). Porpoise clicks were rare, detected at only two stations during exceptional or occasional visits. Monitoring continued into 2024, with results under analysis.	Parc éolien en mer de Saint-Nazaire 2023	No data available
2131439	Operations	Habitat Change Physical Environment	Water Quality Sampling A multisensor sonde measured depth, temperature, turbidity, salinity, and dissolved oxygen along vertical profiles. Niskin bottle collected mid-depth water samples for chlorophyll and suspended matter analysis.	Complete Four-year monitoring (including baseline and operational phases) detected no significant differences between wind farm and control areas beyond natural environmental variability. Statistical analyses confirmed all observed variations corresponded to normal environmental fluctuations.	Parc éolien en mer de Saint-Nazaire 2024	No data available
2131449	Operations	Habitat Change Physical Environment	Sediment Quality Survey Post-construction sediment quality surveys were conducted along the cable route. Soft sediments were collected using a Day grab at 7 stations to analyze granulometry, physicochemical properties, and organic contaminants.	Complete No significant changes in granulometry, physicochemical properties, ecological indices, or contaminant status were observed, except for one station displaying minor granulometric variation.	TBM Environnement 2023	No data available