Octopus numbers off the coast of Cornwall have exploded in what could be the first “octopus boom” in 70 years.
Fishermen have reported finding dozens of octopuses in their lobster pots and cuttlefish traps in a single day when usually they might find one or two a year.
The common octopus is usually rare in UK waters, with the Cornwall Wildlife Trust only recording the species twice a year on average.
Numbers are currently shooting up, however, with one fisherman reporting 150 in his pots and traps over just one day.
The lesser or curled octopus is more common in the British Isles and is found across our seas, whereas the common octopus is only found around the South West.
Matt Slater, marine conservation officer at Cornwall Wildlife Trust, said: “I got really excited when I started receiving messages from our Seasearch divers – not only because sightings of these striking animals are few and far between, but because they’d seen several of them on one dive.
“They are such amazing, alien creatures – one of the most intelligent animals in our oceans – and to witness a population explosion in our local waters would be incredible.”
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 sightings 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.
