Familiar Fins, New Faces and Bizarre Encounters … !!

Ask anyone and they’ll tell you that Scotland has been having a dismal summer this year, low temperatures and rain and wind galore. The weather however isn’t going to stop our dolphins go about their daily business and so we returned (even more determined than ever) to our field site on the Isle of Lewis to try and catch-up with the Risso’s dolphins whom we’ve been studying in this area since 2010. Over the past 6 years, we have discovered much about a relatively little known species and are making headway in ensuring that an area that is crucial to their well-being and ultimate conservation, is protected.

Expecting the worst from a weather point of view, we were pleasantly surprised to find that on our arrival, the storm clouds cleared, the rain and wind abated, and we were lucky enough to get out on the water for 3 days in a row – something that’s almost unheard of in this part of the world … somewhere that’s closer by far to the Arctic Circle than the equator.

On day 1 we were thrilled when after only a very short time at sea we spotted what to us as Risso’s researchers, was the unmistakeable dorsal fin of our study subjects! One fin after the other sliced through the surface and in total we found ourselves amongst a pod of at least eight Risso’s dolphins. Relative to other encounters we’ve had over the years, this group were pretty shy and kept a reasonable distance from our boat (as we did them) but still we managed to get sufficiently good photographs to be able to individually identify each animal. Much to our delight, later analysis showed that each of the eight dolphins encountered were not previously known to us – we had some new kids on the block! Having eight new animals to add to our catalogue equalled a fantastic first day for this year’s field season.

The following day we were back out on the water again, this time in the company of a pod of at least seven Risso’s dolphins. Today however they were much more sociable towards us, with one individual embarking on a very close “swim-by” and eyeballing us from only few meters away – episodes like this warm the cockles of a researchers heart! Even during the encounter, moving from dolphin fin to dolphin fin, I was fairly sure that I recognised a few of the individuals. Later analysis proved me right and it turned out that all seven individuals were already known to us (some with a few newly acquired scars) but more excitingly all seven dolphins had been encountered “together” over multiple years … posing of all sorts of questions including do Risso’s dolphins off the coast of Lewis form long-term social bonds? It would certainly seem that way but it’s early days for these kind of assumptions to be made. As a bit of a bonus, on our return leg back to the harbour we were joined by a group of common dolphins who took great delight in bow-riding, breaching and playing in our wake! Again, it was the subsequent analysis of photographs taken that revealed an interesting – and bizarre – encounter. One of the common dolphins stood out from the crowd as it had a completely unique colouration, unlike any other common dolphin yet documented anywhere in the world. Although it’s quite possible that it could just be an “anomalous” individual, given that in the past few years we’ve documented at least four possible hybrid dolphins (Risso’s and bottlenose dolphins), could it be that this was yet another hybrid individual? 

On day 3 the conditions were not ideal but we were thrilled yet again to find more Risso’s dolphins. As the weather was on the turn photographic evidence was slim on the ground however we were still able to determine that all three individuals were already known to us, with one individual being seen in the group of seven only yesterday! Adding to our discovery of the “anomalous” common dolphin the day before, we spied a lone common dolphin mingling with the Risso’s … there’s certainly strange things afoot in these here waters!!

Unfortunately the clouds, rain and wind returned with a vengeance and we were confined indoors, no getting out on the water for us for a few days at least! However, with three fantastic encounters under our belt (and many many photographs to analyse) there was plenty to keep us busy while we wait for our next weather window.