University whale watchers spot their first Orca of the year

A GROUP of killer whale researchers, in Shetland as part of a two-month long study into the presence of the mammals in waters around the isles, made their first sighting last weekend.

The incidence of killer whales around Shetland have become increasingly prevalent since the early 1990s and rough estimates suggest that the population in
the north of Scotland, from Caithness to the Northern Isles, is around 200.
The new research is being carried out by the University of Aberdeen zoologist Andrew Foote and Volker Deecke from the University of St Andrews. The four-strong team, completed by Alice Rocco and PhD student Harriet Bolt, arrived a fortnight ago to undertake research into the incidences and behaviour of the mammals.

They had their first sighting of killer whales in Mousa Sound last Saturday evening, meaning the two-month long fact-finding expedition is likely to prove more fruitful than Dr Foote and Ms Bolt’s visit last summer, when they caught their first glimpse of the killer whales on the final day of their visit.

That piece of research concluded that the presence of killer whales could be partly to blame for a sharp drop in the native seal population, discovering a correlation between the increasing number of ob­servations of the killer whales preying on harbour seals and the decline of the seal population. The number of common seals in Shetland fell from around 6,000 in 1997 to less than 4,000 two years ago.

This year, they are seeking to build up photo identification of the mammals’ dorsal fins and saddle patches, which are unique to each killer whale, in order to ascertain how many of the same mammals show up in different regions. The most common sightings appear to be in the Bluemull and Yell Sounds, though this may be simply down to the fact that the inter-island ferries are crossing those channels on a regular basis.

Mr Deecke said they were looking to build up a picture of the mammals’ diet and monitor their calls to see if there was a suggestion of social interaction with pods observed in other areas, while they are also going through museum specimens for DNA to try and identify family groups and mating patterns.

“Genetics will always show a more historic estimate of movement going back over a larger time scale,” he said.

The presence of killer, or orca, whales in areas of the Pacific and the way they affect marine life has been a “big bone of controversy”, Mr Deecke said. According to the journal British Birds, killer whales are estimated to have eaten 50 eider ducks, estimated to be one per cent of Shetland’s total eider population, in one recent incident.

“A killer whale is estimated to consume the equivalent of a harbour seal each day, so the potential impact is quite real,” said Mr Deecke.

In October George Anderson, skipper of the pelagic boat Adenia, will again take the researchers out on trips off Lerwick and Muckle Flugga, where they can observe and catalogue pods of whales feeding, often on mackerel, around the fishing nets.

Meanwhile, the researchers are to stage a rescheduled talk on killer whales at the Garthspool offices of Shetland Amenity Trust next Friday (13th June) at 7pm, with free entry.

The research team is heavily reliant on members of the public alerting them to possible sightings and they are asking anyone who spots killer whales to contact the team immediately on 07500 380524, and Mr Foote said they were keen to hear from anyone with photos or other information.

In particular, they are asking watchers to try to get photos of the animals’ dorsal fins and saddle patches, to look out for the size and composition of the group, for any distinctive markings and incidents of predation.

Mr Foote added: “So far it’s been a real pleasure working up here and we’d like to say thank you to all the people on the islands.”