A new paper has been published investigating the distribution and drivers of several beaked whale species in the Bay of Biscay, suggesting they may be present in the Bay year-round.
The data collected by ORCA citizen scientists from Brittany Ferries vessels between 2006 and 2018, was analysed to look at how "encounter rates varied across space and time." These findings are important to increase our understanding and knowledge about beaked whale seasonality and geographic distribution, as well as the factors behind their occurrence in the Bay of Biscay.
The data used for this study was collected by Marine Mammal Surveyors collecting distance sampling data from the bridge of the ferries, and ORCA Wildlife Officers, who live on board, adding a considerable amount of survey effort to the study. Some sightings which were recorded would not have been possible without this effort, for example, recording True's beaked whales in 2018.
Over a third of the world's cetacean species can be seen in the Bay of Biscay, including several beaked whales species. Beaked whales are rare and elusive, spending very little time at the surface of the water, preferring the depths of the ocean. This makes them a difficult species for us to study, and very little is known about their presence in these productive waters.
Data from 244,400km of surveyed water was studied along with 419 beaked whale encounters, including Cuvier's beaked whales, Northern bottlenose whales, Sowerby's beaked whales and True's beaked whales. It showed that all species were generally more frequent in the south of the Bay, on northern facing slopes, except the Sowerby's beaked whale which "showed a preference for both deep waters and shallow shelf waters."
Although there were increased encounter rates during the summer months, especially in sightings of Northern bottlenose whales, beaked whale species were recorded in each of the eight months when surveys were conducted, suggesting these animals might be present all year in the Bay of Biscay. There was an unclear trend in sightings of Sowerby's beaked whales, but they were higher later in the year, and for Cuvier's beaked whales, months were not significant.
It is necessary for surveying to take place during the winter months to confirm whether beaked whales are present in the Bay of Biscay all year round. However, this can be difficult due to weather conditions, the mysterious nature of beaked whales, and survey routes changing during this season.
Citizen science data is starting to give us a much better understanding of what is happening in the Bay of Biscay, which will help us identify conservation priorities.
If you want to get involved and join ORCA as a citizen scientist and contribute to cetacean conservation, there are a number of ways you can do this. Train as a Marine Mammal Surveyor and help us study and monitor important marine mammal habitats, or join us as an OceanWatcher and collect data about whales and dolphins whenever and where you can see the sea.
