Local fishermen along Cornwall’s south coast have also witnessed large numbers of octopus in their lobster pots and cuttlefish traps. One Mevagissey fisherman reported catching 150 octopuses in a day, compared to his usual catch of one or two a year.
The Common Octopus is known for its large eyes, soft bag-like body and tentacles which can span up to one metre. Like other cephalopods, their populations fluctuate dramatically. Huge booms in common octopus numbers have been recorded twice before in Cornwall, once in 1899 and again in 1948.
Warming waters owing to climate change may be increasing the baseline number of common octopuses, but it’s as yet unclear if they have played any role in this latest surge.
Mr Slater said: “We hope this is a sign that octopus populations are healthy in our Cornish waters, but sadly not all of our marine life is thriving.”
He encouraged the public to help record sittings of the species to help study its numbers.
“By taking action for wildlife and recording your marine sightings with us, we can build up a picture over time and confirm if occurrences like this are a one-off or if octopus populations are steadily on the rise.”
Members of the public can record any octopus sightings with the Cornwall Wildlife Trust via its ORKS app or online.