Wildlife: Chasing whales
Andy Foote from the University of Aberdeen is currently leading a team of researchers studying Shetland’s killer whale population. Here, he explains more about the project.
Shetland is one of the best places in Britain to see killer whales, but very little is known about the individuals seen around Shetland coast. Since 2006 I have been compiling photographs from across the Northeast Atlantic, from Iceland to Norway to learn more about the travel patterns of these whales, and so Shetland quickly became a key location in my study.
During the summer, killer whales are seen very close inshore around Shetland and appear to be mainly preying upon seals. However, in autumn large groups of over 50 are seen feeding on mackerel in the offshore waters around Shetland by the fishermen. I have been lucky enough to join skipper George Anderson on the FV Adenia during these trips to see this spectacle and collect more data.
One of the main tools we use to study killer whales is photo-identification. Each dorsal fin and saddle patch (the white area behind the fin) is unique, like a human fingerprint. So we are able to use photographs to investigate whether the same whales visit Shetland each year; if they live in stable social groups; if they travel to Norway or Iceland; if some individuals have particular feeding preferences; and how many whales there are in the population.
By combining photographs collected by the public and those taken on my own research trips, I have a record of over 80 encounters with over 70 individuals photographed around Scotland. The same groups appear to return to Shetland each year during the summer and are also regularly seen around Orkney and Caithness. However they seem to be distinct from the killer whales regularly seen around the Hebrides. Comparing these pictures with photographs taken further afield, we have learned that some Shetland killer whales have also been photographed off the east coast of Iceland.
Watching killer whales hunt seals around Shetland is very dramatic and exciting. They move very fast, hugging the coastline tightly, almost touching the rocks at times, in fact we have noticed one whale has picked up an additional long scar along her body this summer, probably from scraping a rock during hunting.
My collaborator Volker Deecke from the Sea Mammal Research Unit in St. Andrews has been recording their acoustic behaviour and has found that they hunt in complete silence, only emitting a few quiet calls after they have caught a seal. A successful predation by the whales can sometimes be quite difficult to detect, with just a few bone crunching sounds heard on the hydrophone and a great deal of interest from the fulmars hoping for some scraps. At other times it can be very dramatic and the seal can be tossed in the air in a scene reminiscent of the Blue Planet TV series. We try to identify the prey species each time, usually by visual observation, but we also collect small scraps of prey remains from which we can identify the prey species genetically.
Summer is definitely the best time of year to see killer whales from the shore around Shetland, but there doesn’t seem to be a particular hotspot around the islands, they could show up anywhere. However, we have noticed that ordering a meal in a restaurant or arranging to meet up with friends is a sure fire way to guarantee that we will get a phone call on the sightings hotline and have to dash off! The best way for visitors to Shetland to maximise their chances of seeing killer whales would be to spend as much time as possible scanning from high headlands with good binoculars in areas with seals on a clear, calm day. However, hiring a local guide, such as Brydon Thomason, who is in contact with all the local ferries and fishermen, would greatly improve your chances, and Brydon’s help has certainly been invaluable to our research project.
If you are lucky enough to have an encounter with Shetland killer whales then you have a great opportunity to contribute towards the research. You can call us on 07500 380524 with the time, location and heading of the whales and we will try to launch our boat to get more valuable data. You could also try to photograph as many of the dorsal fins and saddle patches as possible and email them to me at a.d.foote@abdn.ac.uk, and I will try to identify them.
The research will continue during 2009 and possibly longer thanks to the support of Scottish Natural Heritage, SEERAD, the Carnegie Trust and the whole Shetland community.
Andy Foote, University of Aberdeen
