Mapping the vulnerability of cetaceans and seabirds to offshore wind farms in French waters: a tool for spatial planning

Dates: 2025–2026

Research team: LIENSs CNRS-La Rochelle Université & Cohabys (ADERA)

In face of European Union’s ambitions to develop offshore wind capacity by 2050, rigorous planning is essential to reconcile energy production with biodiversity conservation. In that agenda, detailed spatial vulnerability assessments are crucial for identifying sites that minimise the impact on biodiversity, including cetacean and seabird populations. We developed seasonal maps of cetacean and seabird vulnerability to offshore wind energy in French Atlantic and Mediterranean waters. We performed habitat modelling using Generalised Additive Models, incorporating monthly averages of physical and biological covariates corresponding to the data collection period. This large-scale analysis is based on fifteen years of standardised aerial and boat-based surveys at sea, covering over 315,000 km in the Atlantic and 110,000 km in the Mediterranean. The study is based on 31 datasets comprising a total of >200,000 records from twelve cetacean and seabird groups. The distribution maps were then combined with species-specific sensitivity indexes and conservation status to produce vulnerability maps for offshore wind farms. Risk factors included collision and habitat displacement for birds, and underwater noise, entanglement and habitat displacement for marine mammals. These maps informed the French national public debate on offshore wind development in 2024 and are currently used by governmental agencies to identify areas presenting the lowest risks for cetaceans and seabirds and to prioritise future wind farm development. The study also highlighted the need to improve data collection, particularly through greater standardisation of practices for data acquisition and archiving. For example, several of the available datasets revealed gaps in observation efforts relating to environmental conditions and spatialisation which posed specific challenges to ensure their inclusion. This work represents the most up-to-date knowledge in France regarding the vulnerability of megafauna to offshore wind turbines. However, it will be essential to update it regularly as our understanding of how species respond to offshore wind farms improves. Finally, we emphasise the importance of integrating ecological knowledge continuously into energy transition strategies to reduce conflicts over marine use and ensure the rational development of renewable energy.

This work has been presented at several international conferences in 2026 (ICES Annual Scientific Conference, European Cetacean Society Annual Conference, World Seabird Conference; see talks and posters for complete reference list) and is published at (update reference).

The species distribution maps as well as the species-specific vulnerability maps and integrated vulnerability maps are made available online on dedicated SEANOE repository:

• El Abdellaoui Mènel, Pettex Emeline, Martinez Ludivine, Dorémus Ghislain, Folliot Benjamin, Laran Sophie, Michez Noëmie, Lambert Charlotte(2026). “Seasonal density distributions of cetaceans and seabirds in French EEZ”. SEANOE. DOI
• El Abdellaoui Mènel, Pettex Emeline, Martinez Ludivine, Dorémus Ghislain, Folliot Benjamin, Laran Sophie, Michez Noëmie, Lambert Charlotte(2026). “Mapping the vulnerability of cetaceans and seabirds to Offshore Wind Energy in French EEZ”. SEANOE. DOI