Octopus boom in British waters is a concern, say scientists

North Wales Chronicle

28-05-2025

Over the last few months, fishers along the southwest coast of England have seen an increase in the number and size of common octopus.
Alan Steer, a crab fisher based in Devon, told Sky News: 'As of February this year, there was just a massive explosion in the population of octopus.'
He added: 'We went from catching nothing to catching 1,000 kilograms a day.'
Fishers have noticed an increase in octopus (Image: Getty)
Steer explained that each octopus weighed between 2.5kg and 3.5kg.
Sky News explained: 'The octopus is a valuable catch, fetching more at the fish market than the crab that many local fleets are designed to fish for.
'And it's just as well, because the eight-limbed creatures are also devouring local crab and lobster species, leaving some fishers empty-handed.'
Steer said: 'Since the octopus have turned up now, we are seeing massive devastation to the crab and lobster and scallop stocks in the pots' as he showed empty crab and lobster shells inside them.
The crab fisher thinks his crab and lobster catches have dropped by around 70%.
While the common octopus is no stranger to British waters, more research is needed to understand why there has been a recent boom, say scientists.
It's possible that warmer temperatures and fewer predators (such as tuna, cod and sharks) could have an impact.
The pots have holes for small crabs and lobsters to exit out of but octopus can also get through these holes meaning they're being caught.
Sky News explained: 'Previous "blooms" of octopus, recorded in 1899, 1950 and 2022, saw the animals stick around for a season or two, before disappearing in cold winters.'
It added: 'The Devon and Severn Inshore Fisheries and Conservation Authority (IFCA) said the escape holes can be closed off if fishers were trying to catch octopus only, in which case they'd have to throw any other catch back into the sea.'
The IFCA's deputy chief officer, Sarah Clark, said the increase in octopus is a 'concern', saying: 'We're going to be trying to gather as much information about octopus and what we do in the next coming months, years, if the octopus fishery remains within the South West.
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'And that's obviously a big 'if', because we don't know if the octopus will be here again next year.'
Today, the support fishers need will be determined as a result of the meeting with the future involving more meetings that will focus 'on collecting data, the impact on other species and how to determine whether the octopus are here to stay.'
'Dr Zoe Jacobs, from the National Oceanography Centre (NOC), said the recent 'marine heatwave', which has seen water temperatures 2.3C higher than average, might be behind the reported early sightings of barrel jellyfish, increased numbers of seabass and pods of dolphins spotted in shallow inshore regions,' Sky News explained.
She explained: 'It may also be behind the recent spike in octopus. We need to improve our monitoring of such species to collect as much evidence as we can to understand if the marine heatwave is indeed driving this sudden influx of warm-water species into coastal waters.'