Common Octopus in open water
Common Octopus in open water

Huge numbers of octopus have been seen along Cornwall’s coastline this month in what experts are describing as a ‘bumper year' for sightings. Cornwall Wildlife Trust’s conservation officers now believe this could be evidence of an octopus population boom – an event last recorded along England’s South Coast more than 70 years ago.

Divers and snorkellers have reported an increase of common octopus in Cornwall, particularly around the Lizard Peninsula. Despite its name, this large species of octopus is rarely seen in UK waters and has been recorded by the wildlife charity just twice a year on average.

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.

matt Slater captured video of common octopus off Porthkerris

“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 fishers 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 as scientists attempt to learn more about their behaviour and abundance.

Common octopus seen on the Lizard Peninsula in June 2022
Common octopus seen on the Lizard Peninsula in June 2022

Massive population booms of octopus are uncommon, but not unheard of. The Marine Biological Association has reported on several major octopus ‘plagues’ along the South Coast of England from Land's End to Sussex; first in 1899 and most recently in the summer of 1948.

Matt continues: “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. 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.”

Cornwall Wildlife Trust is encouraging members of the public to record any octopus sightings with them via its ORKS app or online at www.erccis.org.uk/share-sightings.

The large body of a common octopus
The large body of a common octopus

Photo credit: Shannon Moran

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