Back in the 1990s WDCS provided funding for the Western Isles Risso’s Dolphin Project on Lewis and studies then took place over a period of about 5 years - and now more than a decade later the studies recommence! With the advice and assistance of Tim Atkinson, one of the project investigators of the original surveys, we hope to collect some new and updated information about the Risso’s dolphins off the Eye Peninsula. This is important for a number of reasons, not least of all because there are less than a handful of sites in the world where Risso’s dolphins calve so close to shore and because Scotland is in the process of designating a network of marine protected areas by 2012, to meet its international obligations – and we think this population of Risso’s deserves to be included!
No population-level information is available on trends in abundance, incidental mortality rates or even the distributional range of the populations of Risso’s dolphins in Scotland or the UK. Risso’s dolphins are oceanic dolphins that feed primarily on squid, octopus and cuttlefish and seem predominantly to feed in deeper waters. They are often found around interesting topographical features, where productivity is enhanced by mixing waters, such as seamounts and escarpments. They also inhabit a few coastal sites where the continental shelf is narrow and close to shore, including here! Previous studies indicate that the waters around north Lewis, along with a few other sites on the west coast of Scotland (including Tiree, Coll and Ushinish Peninsula, South Uist) are important for Risso’s dolphins.
We haven’t seen any Risso’s yet (we’ve only been here a few days!) and the reports this year so far are few and far between. Results of the surveys 10 years ago showed that Risso’s dolphins are found offshore in deeper waters and in large groups between the months of May and July. In August and September, however, the dolphins regularly moved into coastal bays or near-shore in the waters around Stornoway, foraging on their own or in small groups. Tim and his colleagues built up a large catalogue of dorsal fins to identify individual animals that we hope to update and add to (scientists in the Ligurian Sea resighted a Risso’s dolphin from 15 years ago, how cool would it be if we could do the same thing!) – if we’re fortunate enough to find the animals… And so now we watch, cross our fingers and wait for them to turn up!
Our aim is to determine the significance of the coastal waters of Lewis for the Risso’s and all other cetaceans. We will collect basic land-based observation data from the headland on the Eye Peninsula, a favourite haunt of the dolphins of old, and we’ll collect opportunistic photo-identifications from small boats whenever the weather permits - which is not as often as we would like in these parts!
Besides the Risso’s there’s a diversity of marine life here that would be hard to beat anywhere else in the British Isles. From our headland vista, we’ve encountered locally breeding arctic and great skuas flying overhead, gannets dive bombing from north to south in the minch surrounding us and porpoises, common dolphins and basking sharks all feeding in the rich and productive waters. We’ve already had a minke whale surface so close to shore in front of us that we could hear it exhale and almost smelled its breath as it rose to the surface.
We’ve experienced the famous Hebridean winds over the last couple of days but these are set to drop for the next few days so we’re off to grab supplies and prepare to head out on the survey boat…