The number of sea turtles visiting waters off the coasts of Devon and Cornwall may have been boosted.
Leatherback turtles were the most common sightings
A study by biologists from the University of Exeter's Tremough Campus, in Cornwall has shown an increase in turtle sightings.
There has been a rise in loggerhead and Kemp's Ridley turtles in UK and French waters in the past 20 years.
It is thought protective measures put in place in the United States and Mexico could be responsible.
More than 300 turtle sightings have been recorded in the region's waters over the past century - 225 of them in Cornwall.
Leatherback turtles have been the most frequently sighted species.
Matthew Witt from the University of Exeter said: "Following a severe decline as a result of human activity in the first-half of the last century, we can now see the positive effect that recent conservation efforts have had on these turtle species."
Protection measures have included the introduction of turtle excluder devices in fishing nets and hatcheries to protect eggs.
"Though numbers are increasing, it is still incredibly rare and special to see a marine turtle," Mr Witt said.