Experts: Rare visitors having fun

Porpoises are a regular sight on the Firth of Clyde, but dolphins are rare visitors, according to experts.

The Clyde dolphins have likely found a suitable fish stock since taking up residence in the river this summer, according to Morven Summers of the Hebridean Whale and Dolphin Trust.

“Bottlenose dolphins are a coastal species and move around inshore waters in search of food. Off the west coast, we have a relatively small population, about 30 to 40 animals, inhabiting the area between Skye and Kintyre, including the Clyde basin.

“We seemed to have a number of bottlenose dolphins off the west coast of Mull this summer, too.

“Bottlenose dolphins are much larger than porpoises – Scottish dolphins can reach almost double the length of a porpoise. Dolphins are also much more gregarious, approaching boats and leaping clear of the water, while porpoises are shyer and more elusive. Porpoises have a smaller triangular fin, which you can see briefly when they break the surface, while bottlenose have a more sickle-shaped, larger dorsal fin. We can identify individual dolphins from their dorsal fins – which are as unique as fingerprints to humans.”

In 2018, a pod of killer whales spent several weeks in the Clyde, feeding on seals. The organisation encourages people to record their sightings of whales and dolphins around Scotland on the Whale Track app.

And as for whether the Clyde dolphins are able to recognise Tonka, Morven said: “Dolphins are wellknown for approaching vessels to ride the bow wave. We’re not 100% sure why they do this but suspect that the main reason is simply to have fun. It has probably come from an adaption from surfing on large waves and nearshore breakers, indeed they’re also seen to do it on the pressure wave created at the front of the great whales too.

“It’s impossible to say whether the Clyde dolphins have come to ‘know’ the Clyde Charters vessel, but it sounds like they enjoy interacting with it.”