WDC’s field team in the Outer Hebrides recently recorded this great video footage of Risso’s dolphins in the surrounding waters.
Stomach contents from strandings data from a limited number of UK Risso’s dolphins shows that their primary prey is octopus. However, a recent report by scientists shows that the relationship between the observed distributions of Risso’s dolphins and octopus (Eledones cirrhosa) is not as clear cut as we might expect in Scottish waters.
Whilst it would make sense that important areas for octopus could be defined as ‘critical habitat’ for Risso’s dolphin, it has not been possible to determine that Risso’s dolphins prefer areas containing good numbers of octopus or use them with greater frequency than any other area. WDC believe that it’s most likely that this link cannot be made as the existing data are not detailed enough.
A larger Risso’s dolphin sightings dataset, including fine-scale data, is required to understand where this species occurs and especially where it is feeding. WDC is helping to fill this important data gap.
In addition to modelling the distribution of octopus, direct modelling for Risso’s dolphin habitat is required. As is the collection of more octopus and other important prey data distribution.
In the meantime, we know that the Isle of Lewis has always been one of the best places to see Risso’s dolphins in the UK. Our data is starting to show that the group sizes seen today are smaller than they were in the 1990s. MPA protection for Risso’s dolphins can’t wait for the collection of all this data – we have enough to be confident in this area of critical habitat.
If you would like to support MPAs for Risso’s dolphins and other Scottish whales and dolphins, please write a letter to the Scottish government.