When Chris Chesterfield goes to pull up his pots, he usually expects cuttlefish or spider crabs. But lately the Cornish fisher has been finding himself ambushed – and outnumbered.
“You’ve only got one or two arms pulling them up,” he says, “and they’ve got eight pulling you down.”
Unprecedented numbers of octopuses have been reported in the waters off Cornwall in recent weeks, prompting celebration and concerns of a “population explosion”.
“I’ve been fishing for 40 years and I’ve never experienced this amount,” says Cameron Henry, from Mylor, who fishes with his two brothers.
He first became aware of the increase in late May, when he started pulling up lobster and cuttlefish pots that were conspicuously empty after an eight-legged thief got to the bait or bounty first. “We had no shellfish – only remains of shellfish.”
Within days Henry was catching the culprits too, sometimes two or three to a pot: “You can imagine how fun it is to get them out.”
For Chesterfield, who operates alone from Mevagissey in his 30ft trawler, the octopus overload poses an even greater logistical challenge.
The largest specimens stretch 1.2m (4ft) when suspended over the deck – if you can get them to stay still long enough, he says. “They just throw their tentacles over the top of you and turn inside out, literally. When they come out of the pot, they stick to the deck, stick to your legs – it’s endless.”
In one day in early June, Chesterfield says he caught 260kg of octopus, amounting to about 150 creatures. In a typical year he would expect to catch half a dozen.
“There’s been loads of days when you’re pulling 100kg, no problem at all,” he says. “Sometimes there’s five or six in one pot.”
The Cornwall Wildlife Trust, which coordinates volunteer monitoring of local marine life, says the “huge” numbers of octopus sightings in the region recorded not only by fishers but divers and snorkellers point to a rare population boom.
Despite its name, the common octopus (Octopus vulgaris) is a rare sight in British waters, says Matt Slater, the trust’s marine conservation officer. “In an ordinary year, we’d only expect a couple of sightings and a couple of very excited divers – but now we’re getting reports all the time, which is great.”
Like many octopuses, the species lives only one or two years but produces as many as 500,000 eggs, meaning favourable conditions can lead to massive fluctuations in populations.
According to records kept by the Marine Biological Association, the last such event along England’s south coast was more than 70 years ago, in the summer of 1948. Earlier a “plague” of octopuses was described in 1899.
“It got to the point where fishermen were really worried about their livelihoods,” Slater says. “They were finding them in rock pools and even laying eggs there, which is not normal.”
Although octopuses are considered by some to be a delicacy, there is less demand for them from UK consumers than for the crustaceans they eat, leading to concerns among fishers that they would be competing for their catch this summer. “We’re seeing so many that it wouldn’t take them long to fish out an area,” Henry said.
He has readily sold the octopus that he has caught so far, but warned that if numbers continued to spiral it could pose a problem: “You’ll end up flooding the market, the price will go out and you’ll end up not being able to get rid of it.”
He and Chesterfield say that sightings have dipped in recent days, suggesting that this particular consortium may be moving on – to venture either around Land’s End or out to sea.
It is, however, possible that octopus booms could become more frequent in the future. Like jellyfish, octopuses have been found to be adapting faster than other species to the changing marine ecosystem. Many species have already been found to have expanded their ranges with warming waters, while a study published last year found octopuses may also be able to withstand changes in acidity levels better than other species.
Slater, at least, is enthusiastic about the boom. A card-carrying member of the cephalopod squad, he used to work at an aquarium and says individual animals came to recognise his face and favoured him over other staff.
“A plague of octopus, for me, is something to be celebrated,” he says. “I’ve been hoping that one day I might see one of these big population explosions, and it feels like this could be a bumper year.”
Slater encourages members of the public to report any octopus sightings on the Cornwall Wildlife Trust’s website – but Henry and Chesterfield, on the frontlines, fear being overrun.
Both say they “humanely dispatch” their octopus catch quickly with a knife between the eyes, to the creature’s central brain. That is so “we haven’t got them crawling all over the boat, like in previous years”, says Chesterfield. “They were long, hard days until we found that out.”
