The water around the British Isles suddenly seems crowded as a number of species that are not local to the region are being sighted. Experts believe the presence of these rare cetaceans from tropical climates shows how global warming is pushing the mammals to look for other safer habitats.
Tropical marine mammals like the the pygmy sperm whale, the Fraser’s dolphin and the Cuvier’s beaked whale are regularly being seen in the western Britain waters nowadays that were not earlier present here.
The melon-headed whale, a squid-loving relative of the killer whale, has also been seen in the Channel, off the coast of Brittany. Some experts believe that the giant 16 metre gray whales might also be soon seen in the water around Cornwall and in the Irish Sea.
“We are now seeing a number of species far from home, and they probably will continue to recur with increasing frequency,” said Peter Evans, director of the Sea Watch Foundation. “Several are normally found off west Africa. For the moment they tend to be seen at times of year when our sea temperatures are at their warmest. Whales and dolphins can cope with a wide range of temperatures but their fish and squid prey tend to be more constrained, and their ranges are extending significantly northwards.”
He said that the mammals are following their favorite food which are now increasingly being found in the British seas.
This Fall a dwarf sperm whale was spotted in Mounts Bay, Cornwall, while a pygmy sperm whale, its close relative, was found beached on Seil island, near Oban. They were both a big surprise.
“They are rarely seen even where the populations are known to exist,” said Evans. “If the fish are extending their range, as we know many are, then the whales and dolphins will follow. Anchovies, for example, were really quite scarce in the North Sea 10-20 years ago. Now they are widespread and may be why the common dolphin is now a regular in the North Sea.”
“The behaviour of different fish, if they shoal or don’t shoal, for example, requires a fair bit of understanding, so once a species has learned a feeding strategy they will follow rather than learn a new technique for a new prey.”
Evans warns that if the planet continues to get warmer, soon the gray whale might not be an alien species in British seas.
“They migrate up the west coast of north America, from Mexico and California up to the Arctic and, of course, could go no further. But now the Northwest Passage is open it is very possible they may cross the North Atlantic.
“Gray whales were seen last year off the coast of Israel and off Barcelona this year. Such a remarkable appearance in such a strange location reinforces the pattern we are seeing.”
In the current century, 29 species of dolphins and whales have been recorded in the British Isles and Irish seas. The common dolphin, striped dolphin, minke whale and humpback whale are among those species where numbers sighted have increased since 1980.
But it is not just the whales, even other sea mammals are increasingly being seen in new regions like the bearded seals from the Arctic have been seen off the coast of Fife, east Scotland according to Callan Duck, a senior research scientist at the Scottish Oceans Institute at St Andrews University.
“The change in climate and the food chains is definitely having an impact in the species we are seeing, but I think you have to remember to factor in how much better we are at spotting and recording these mammals. Good digital cameras are really accessible now, and so everybody has the opportunity to identify what they have seen – so the whole process of reporting sightings is much more accurate and efficient.”
While improved technology can be a reason for increased sightings of species, the changing animal behaviour around the world cannot be entirely overlooked and climate change seems the only probable reason for the species migration.