Science at UM [S04-ep17]: Decoding Dolphin Whistles
This week on *A l’UM la science*, Loïc Lehnohff and Bastien Mérigot, researchers at the Marbeclaboratory, attempt to decipher dolphin communication to combat accidental dolphin bycatch. The report takes us to Celimer to introduce us to biologging. Finally, our last-minute guest, Annaëlle Francia, presents the program for 8 Days of Biodiversity. A show airing every Wednesday on Divergence FM 93.9.
The first sailors in the Vendée Globe, who set sail from Les Sables d’Olonne last November, must have noticed a significant change in the Bay of Biscay upon their arrival in late January. Not a single trawl in sight, not a single net, not a single deep-sea seine. And for good reason: since January 22, 2025, fishing vessels over 8 meters in length have been banned from the cold waters of this part of the Atlantic until February 20.
The goal? To give some breathing room to dolphins whose populations are increasingly threatened by so-called bycatch. In 2019, the number of dolphins killed unintentionally in this way was estimated at 11,500 (8,900 in 2021), while the International Council for the Exploration of the Sea (ICES) sets the threshold for endangering this population at 4,900.
On October 23, 2023, under pressure from a European directive, the Minister for Maritime Affairs issued a decree banning fishing in the Bay of Biscay for four weeks during the winters of 2024, 2025, and 2026. While the measures taken in the winter of 2024—much like those against neonicotinoids—were largely rendered ineffective by a series of exemptions that were later deemed illegal by the Council of State, the ban in the winter of 2025 is proving to be significantly stricter, much to the chagrin of fishermen.
So is it possible to reconcile industrial fishing with ocean conservation? Scientists are working to develop devices that could help minimize casualties by alerting dolphins and other small cetaceans to the presence of these nets. If forewarned is forearmed, how can we communicate with these animals, whose intelligence is well established? By using acoustic beacons! Bio-inspired beacons are being developed as part of the DolphinFree project led by Bastien Mérigot, a researcher at the Marbec marine biology laboratory. Together with Loïc Lehnohff, also a researcher at Marbec, they have used artificial intelligence to study the sounds these marine animals emit in the presence of the beacon or fishing nets. They discuss their publication Characterization of Whistles Using Artificial Intelligence: Responses of Short-beaked Common Dolphins (Delphinus delphis) to a Bio-Inspired Acoustic Mitigation Device.
In the second half of the program, we head to Sète, where Laurent Dagorn from theMarbeclaboratory takes us to the Center for Coastal and Marine Research (Celimer) to see the biologging platform—a technique for tagging marine animals with transmitters that allow researchers to track their movements.
At the end of the program, Anaëlle Francia, a master’s student in environmental and biodiversity management, gives us the schedule for the 8 Days of Biodiversity, which will take place at various locations in Montpellier from February 12 to 19.
At UM Science, you’ve got the program—let’s get started!
Co-production: Divergence FM / University of Montpellier
Host: Lucie Lecherbonnier
Interview: Lucie Lecherbonnier / Aline Périault
Reporting and editing: Lucie Lecherbonnier
Director: Robin Laillou
Tune in to the show “A l’UM la science” on Divergence FM 93.9
