Risso’s dolphin photo ID

Posted by Brydon Thomason on Monday 16th August 2010 | Sea Mammals in Shetland

Once again, it has been a good season for encountering these fascinating dolphins. We enjoyed several encounters through out the season, one of which in early May proved to be very interesting and indeed informative.

After photographing a pod on Bluemul Sound whilst editing images I came across an individual with a very distinct scar on its left side, just bellow the dorsal. I immediately thought that this scar was familiar to me and that I had seen it on a dolphin before but couldn’t quite relate to when or where I had seen it on another animal.

It was not until some weeks later, I came across images on my laptop taken by Dr Volker Deeke (a member of the Shetland Nature team) off East Yell last summer. In his sequence he had photographed this same individual, clearly identifying it as the same animal as I had encountered.

In many ways it was no surprise to confirm a positive ID and a match (although this is the first time photo ID’s have been confirmed in Shetland), as many of us already presumed that sightings in Shetland each summer probably relate to the same pods (as is the case with returning Killer whale pods) and that these pods are probably quite faithful to particular stretches of water each year. Risso’s certainly show a preference for the waters around the North east of Shetland especially the waters around Unst, Yell, Fetlar, Skerries and Whalsay. Sightings are however recorded from other locations pretty much annually.

Jane Evans and a team of researchers from the Scottish Oceans Institute began some research on these somewhat enigmatic sea mammals this summer. Mainly working in the waters off Unst, Yell, Fetlar and Skerries more often than not they would locate the pods on a daily basis in the same areas, often using hydrophones both to locate and record the enthralling vocalisations they use to communicate under water. We look forward to their return in 2011 and giving them our continued support.