Dolphins could disappear from the coast of Scilly and other parts of the South West in four years unless action is taken to protect them, marine experts have warned.
More than a dozen species of dolphin, whale and porpoise are regularly seen off the Islands, as well as Dorset, Devon, and Cornwall.
They are often spotted by passengers on the Scillonian.
But a report analysing 14 years of records shows an “alarming decline” in the sighting of some species in the area, particularly bottlenose dolphins.
It also shows an increase in the number of dead dolphins washed up on beaches.
The decline is blamed on dolphins being caught in nets between fishing boats.
The joint report by Marine Connection and The Wildlife Trusts highlights the 14 species of cetaceans regularly spotted off the South West, dubbed England’s ‘Dolphin Coast’.
Lissa Goodwin, fisheries and policy officer for Marine Connection, said: “Entanglement in fishing gear is the number one cause of death in stranded dolphins, particularly common dolphins and harbour porpoises.
“There is a very real danger that we could be seeing the last of the bottlenose dolphins off the South West shores. We need to take urgent action.?
Sightings peaked at 335 in 1992 but by 2004 the number had fallen to 60. Just 16 have been reported in the region this year, an all-time low.
The South West Dolphin Report was launched on Monday night.