ABERDEEN, Scotland -- White-beaked dolphins have almost completely disappeared from the West Coast of Scotland in the last few years. Once one of the most commonly seen dolphin species, new research has found that they are now rarely sighted in these waters, with climate change the most likely cause.
White-beaked dolphins are found only in the shallower waters of the northern North Atlantic and, until the late 1990s, the West Coast of Scotland had some of the highest numbers of this species in Europe.
However, by 2003, this cold-water species had been replaced by the common dolphin, a species found only in warmer waters. This change has been accompanied by an increase in water temperatures around the UK of up to 0.4oC per decade since 1981.
This is the first time that climate change has been found to be directly linked to a change in occurrence of a whale or dolphin species.
These findings have been made possible thanks to Scotland’s long history of collecting records of stranded animals and because it has been a Mecca for scientists studying whales and dolphins for many decades.
A team of researchers from the University of Aberdeen, the Scottish Agricultural College in Inverness and the National Museums of Scotland in Edinburgh have been examining trends in strandings of whales and dolphins since 1948.
They found that cold-water species, such as the white-beaked dolphin, are now stranding less frequently, while warm-water species are being recorded more frequently. This includes the striped dolphin, a warm-water species that had not been recorded in Scotland before 1988. These findings follow the pattern expected if the warming of the sea around the UK is responsible for these changes.
The research, which will be formally published in the scientific journal Biological Conservation in August 2005 but is currently available online, found that these trends in strandings are mirrored in changes in sightings of dolphin species, with the cold-water white-beaked dolphins being replaced by warm-water common dolphins.
Colin MacLeod, a Ph.D. student from the University of Aberdeen, said: “In the 1990s white-beaked dolphins were commonly seen on the West Coast of Scotland, but recent surveys conducted by students from the University of Aberdeen have only seen one group of white-beaked dolphins since 2001 and that was in the first year. This was a great surprise and got us wondering what was going on.”
Scientists predict that the current trend of warming waters around the UK will continue in the foreseeable future. If it does, it is likely that white-beaked dolphins will continue to disappear from areas where they were once common, such as the East and West Coasts of Scotland and the southern North Sea.
The loss of these acrobatic, black-and-white dolphins from waters around the UK would represent a serious threat for the species as a whole, as well as a loss of one of the UK's most distinctive dolphin species. What will happen to the white-beaked dolphins that once occurred in these areas is currently unclear and further research is required to identify the fate of these dolphins as the seas warm.
These findings are also a concern for the North-west of Scotland, where whale and dolphin watching has become an important part of the economy in recent years. The changes seen so far may only be the start of many changes caused by increases in water temperature and the effects of such changes on Scotland’s whale-watching industry are unclear.
Cally Flemming from the Hebridean Whale and Dolphin Trust, a charity dedicated to the conservation of these animals on the West Coast of Scotland, said: “Marine wildlife tourism, especially whale watching is an increasingly important industry for the West Coast community. In 1999 whale watching alone, contributed approximately £8 million pounds to this fragile economy and it continues to expand and support many jobs.
Mr MacLeod added: “The disappearance of white-beaked dolphins from the West Coast of Scotland should be a wake-up call both for the general public and politicians alike.
“It shows that climate change is not something that will only affect people living in far off corners of the world in the future, but is already affecting Scotland’s wildlife”.
This research has implications that reach well beyond the West of Scotland. Mark Simmonds, from the Whale and Dolphin Conservation Society, said: “Climate change is the greatest threat to all living things and, as this latest research shows, the whales and dolphins are not immune from this.
“The sea is not just one big homogenous habitat for these animals and certain areas and certain conditions are important for their survival. As human activities degrade the marine environment, so the survival prospects for our native marine wildlife decline. We need to do everything in our power to stop this.”
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