19th April 2018
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Killer whale studies over for now

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A TEAM of killer whale researchers who spent the summer in the isles examining the behaviour and habits of orcas recently completed their studies in and around the isles for this year with a trip on a Shetland pelagic trawler.

For the second successive year the team, led by Andy Foote from the University of Aberdeen, spent a week on the Adenia, skippered by George Anderson, on its trip to catch its annual mackerel quota between Shetland and Norway.

Mr Foote has been joined by Volker Deecke from the University of St Andrews and former PhD student Harriet Bolt, who is now planning to continue living and working in the isles.

She described it as a “really successful week” during which they managed to get identifications of 30 newly-sighted killer whales and matched two of the whales to those they had seen on the same trip last year.

“We saw over 100 on one trip – that’s as many as we can say, though the skipper thought it was more than that,” Ms Bolt said. “They’re mammals we’d never have seen if we hadn’t been with the Adenia.”

Ms Bolt added she wanted to thank the crew of the boat as well as Scottish Natural Heritage, the Scottish Executive, Carnegie Trust and Aberdeen University for their support, along with members of the public who have got in touch to alert the team to possible sightings since May.

During their first visit last year, the team discovered a correlation between the increasing number of observations of killer whales preying on harbour seals and the decline of the common seal population, which fell from around 6,000 in 1997 to less than 4,000 in 2006. Rough estimates suggest that there are around 200 killer whales in the waters between Caithness and the Northern Isles.

This summer the researchers were able to match several killer whales spotted in the isles to mammals photographed in Iceland during the 1990s for the first time, suggesting they may have only recently migrated to the seas around Shetland. The research is expected to continue next summer.