Octopus surge spreads up UK coast as far as Scotland, study finds | Marine life
Record numbers of octopus found off the south-west coast of England last year have spread as far as Scotland and Wales and are transforming the fishing industry and marine ecosystem, a study has found.
An increase in the incidence of one of the world’s most intelligent invertebrates was first recorded in 2025 off the south coast of Devon and Cornwall.
A new study, based on scientific research, underwater monitoring and observations by recreational divers and snorkelers, has found that octopuses are spread along the northern coasts of Devon and Cornwall, and have been seen as far afield as Wales, Dorset, East Sussex and Scotland.
“This is pretty unusual,” said Bryce Stewart, a senior researcher at the Society for Marine Biology and lead author of the study. “We’ve had blooms before, but everything I’ve seen tells me this is the biggest bloom we’ve ever seen, it’s quite different.”
Common or Mediterranean octopus, octopus vulgarisIt is endemic to UK waters but is normally found in such small numbers that it is rarely seen. The sudden increase in population is being caused by a combination of a mild winter followed by a warm breeding season in spring, and researchers say the increasing numbers in UK waters are likely to be linked to warming seas and wider changes in the marine environment.
“Now that we have warmer waters that are much more suitable for these animals, we’re seeing a huge increase in their numbers,” Stewart said.
The current surge has sparked increased public interest, with hundreds of divers and snorkelers helping scientists investigate the thriving octopus population.
The bloom was mixed news for fishermen. Those relying on traditional shellfish have been hit hard as octopuses, highly effective predators, often target crabs and lobsters in fishermen’s pots. But others made money by selling record amounts of octopus.
Stewart said octopus catches had increased by 7,700 per cent in 2025 and last week a record 100 tonnes of octopus were sold in one day at Brixham market in Devon, where most of the catch is sold.
“While some fishermen have had to sell their boats due to the impact on crab and lobster populations, others are doing extremely well,” he said.
Stewart said that the octopus influx also disrupted the marine ecosystem. In addition to preying on shellfish and some other fish, the octopus also provided food for seals, conga eels, and the rare risso dolphin. “This is a shake-up of the entire ecosystem,” he said.
