21 Fin whales spotted in Irish Sea

03/06/2011 09:15:07 Ocean giants invade south west Britain
June 2011. One of the largest ever known gatherings of Fin whales in British waters has recently been observed in the Celtic Deep, 50-70 nautical miles off the coasts of north Cornwall and south west Pembrokeshire. On the afternoon of the 21st May, some 21 Fin whales were observed in the Celtic Deep, with the gathering of whales extending over at least ten miles of ocean.

The whales were spotted by scientists Becky Scott, Cheryl Yarnham and Steve Hughes from the marine conservation charity MARINElife.

Team leader for MARINElife Becky Scott explained: "We saw five groups of Fin whales in little over half an hour, in group sizes of up to seven. The whales were blowing frequently and some were lunge-feeding near the surface, it was absolutely fantastic. Luckily, many of the other scientists onboard were able to share this amazing spectacle with us."

Biscay Fin whales
Dr Tom Brereton, MARINElife Research Director commented: "We have been monitoring Fin whale numbers in their Bay of Biscay stronghold for over 15 years, so we are used to seeing large numbers, but to see so many within British waters in close proximity is unprecedented and an exciting new discovery."

The team of MARINElife researchers are currently on a three-week research cruise (18th May -9th June) conducting whale, dolphin and seabird surveys on board the Cefas (Centre for Environment, Fisheries and Aquaculture Science) research vessel, the R.V. Cefas Endeavour. The chief aim of the Cefas survey is to assess the status of schooling fish such as anchovy and sardine in the Celtic Sea and English/Bristol Channel, by fishing trawls and echosounders.

Krill and Sand eel swarms
Having a team of fishery experts on the ship has proved helpful in our understanding of why the whales may be present. Dr Jeroen van der Kooij from Cefas commented: "acoustic echosounders detected dense layers of krill as well as sandeel schools in the area, both of which are known to be key food sources for these animals."

Increasing occurrence or large whales
Due to a lack of surveys in the past, it is unclear if Fin whales have always been present in the Celtic Deep in the spring, but they are certainly rare during the summer months when most surveys take place. However, recent survey work by the Irish whale and Dolphin Group, the Sea Trust and Sea Watch Foundation indicate that Fin whales and other large whales are being increasingly encountered in the Irish and Celtic Seas. A northward shift in distribution of these animals and their prey due to climate warming is a likely explanation.

Climate change moving species northwards?
Dr Colin MacLeod, MARINElife's Chief Scientific Adviser and an expert on whales and climate change explained: "This is one of many changes in whales, dolphins and porpoises which scientists are discovering and which are thought to be driven by climate change. As well as the movement of Fin whale into UK shelf waters to feed, these include declines in the distribution of White-beaked dolphin in the west of Scotland, the movement of Common dolphins into the North Sea and, most surprisingly, the appearance of a Pacific Grey whale in the Mediterranean last summer.

These changes indicate the extent to which climate change is affecting our marine animals, and if it is affecting these top predators to such an extent, it is likely that it is also affecting other marine life further down the food chain, including species which are commercially important for the fishing industry."

The MARINElife surveys form part of a wider study of marine animals off south west England as part of the Charm III project, which involves 17 French and UK research institutes studying and mapping biodiversity and human activities in the Channel.

MARINElife data is important in helping to identify marine protected areas for wildlife around our shores and in ongoing research to assess climate change impacts and other threats to whales and dolphins.