Cetacean sightings in the Bay of Biscay (GBIF map)

One of the largest reservoirs of cetaceans in Europe

With close to 90,000 sightings recorded in the open biodiversity databases (GBIF), the Bay of Biscay is among the best documented areas in Europe for cetaceans. Around ten regular species have been reported there, from the tiny harbour porpoise to the deep-diving sperm whale, by way of the immense fin whales.

The common dolphin, king of the bay

The common dolphin (Delphinus delphis) dominates by a wide margin, with more than 27,000 sightings, close to a third of the total. Next come the common bottlenose dolphin, the harbour porpoise, the long-finned pilot whale and the striped dolphin. The large cetaceans, fin whale, sperm whale, Cuvier’s beaked whale, keep mainly to the deep waters of the slope and the submarine canyons.

A caution about survey effort

A map of sighting density does not only reflect the real abundance of the animals: it also records where and how much people are looking. Cross-Channel ferry routes, aerial scientific surveys (SAMM, ObSERVE) and shipboard ones (PELGAS, run by Ifremer), and whale watching trips concentrate the reports. The high densities along the continental slope nevertheless remain a robust biological signal: this is where the depth drops from 200 to 4,000 metres and where food is abundant.

Further reading

Cross these sightings with the conditions of the environment: plankton and temperature seen from satellite, observation hotspots in France, where to watch cetaceans, diets and the most frequently recorded species in France. The complete list of marine mammals of France records 32 cetaceans and 8 other marine mammals for this seaboard, with the status of each.