ONE after the other they came, drawn to the lethal shallows by the distress calls of the dying. It was the worst mass stranding of marine life on the British coast for 27 years.
At least 21 common and striped dolphins died yesterday after leaving the open sea and heading up a river in Cornwall, in scenes described by one onlooker as "carnage".
Experts believe a pod of about 15 mammals was trapped after chasing large shoals of fish attracted by a massive bloom of algae caused by the recent heatwave.
The dolphins, whose echo locators become confused and disoriented in rivers and shallow estuaries, carried on up the Percuil River near Falmouth before beaching in the shallow waters of Porth Creek.
They sent out distress signals which caused other dolphins to swim inland as well.
A huge rescue operation was launched in an attempt to treat the remaining live dolphins and send them back out to sea.
But Cornwall has experienced soaring temperatures over the past couple of days and the hot, dry conditions caused the skin of most of the stranded dolphins, including one pregnant cow, to dry out, bringing dehydration and death. The crew of the Falmouth RNLI Atlantic 75 inshore lifeboat was first at the scene to find many dolphins already dead, while others struggled in the shallow waters or on the river edge.
Volunteers counted between 15 and 20 dolphins that had already died and up to 10 more were found suffering in shallow water. One had to be humanely killed immediately because of its bad condition.
Helmsman Dave Nicoll branded the scene "carnage".
He said two of his crew got in the water with the dolphins. "It was a horrible scene of carnage with bodies everywhere, but we were doing our best to help those who were alive and succeeded in getting five back into the water.
"I can't say I've seen such a terrible scene as that which confronted us when we first arrived in the creek – it was horrific.
"RNLI crew training is extremely thorough, but this took all our skills and more besides. We are only glad we were able to help.'' RNLI crews managed to save seven of the stranded animals and the last two were taken out to deep water in stretchers attached to boats.
After the procession of boats made its way downriver, it was followed by a pod of about 60 dolphins.
Mr Nicoll said: "It was extraordinary to see. I was very relieved when the two we rescued in stretchers swam away to the others."
The Cornwall Wildlife Trust, vets and volunteers joined the massive rescue operation in which teams of conservationists, divers, coastguards and local government workers all tried to refloat the surviving mammals.
Tony Woodley, national spokesman for British Divers Marine Life Rescue, said: "Logistically, a rescue like this is a minefield. It is very difficult to manage.
"You have to get all the dolphins together. If one or two leave the river system, they will just come back to rejoin the main social group."
There were also reports of smaller strandings on nearby Froe Creek and in shallow water near Falmouth.
Mr Woodley added: "We haven't seen a stranding anywhere near this scale since 1981, when pilot whales were beached on the east coast. This is extremely rare."
• Striped dolphins are closely related to the common dolphin.
• They are so called because of the characteristic blue and white stripes on their flanks.
• They are very acrobatic, able to leap up to seven metres out of the water.
• Striped dolphins are pelagic, or deep-sea, mammals and are not generally considered to be a coastal species, unlike the common dolphin.
• They travel in groups of up to 100 and feed on shoals of small fish, squid and octopus.
• Adult males grow up to 8.5ft long and weigh up to 160kg. Females grow up to 8ft and weigh up to 150kg.