Octopus surge spreads up UK coast as far as Scotland, study finds

Record numbers linked to warming waters is mixed news for fishers, with shellfish catches down but octopus catches booming

Record numbers of octopuses found off the south-west coast of England last year have now spread as far as Scotland and Wales and are transforming the fishing industry and the marine ecosystem, according to a study.

The surge in sightings 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 surveys, underwater monitoring and observations from recreational divers and snorkellers, has found octopuses have spread along the north coasts of Devon and Cornwall, with sightings as far afield as Wales, Dorset, East Sussex and Scotland.

“It is pretty extraordinary,” said Bryce Stewart, a senior researcher at the Marine Biological Association and lead author of the study. “We have had blooms before but everything I am seeing is telling me this is the biggest bloom we have seen, it is quite different.”

The common or Mediterranean octopus , Octopus vulgaris , is native to UK waters but ordinarily in such small numbers that it is rarely seen. A sudden increase in the population – a bloom – is caused by a combination of a mild winter followed by a warm breeding season in the spring, and researchers say the surging numbers in UK waters are likely to be linked to warming seas and wider changes in the marine environment.

“Now we have warmer waters much more suited to these animals, we are seeing a huge increase in numbers,” Stewart said.

The current bloom has sparked growing interest from the public, with hundreds of divers and snorkellers helping scientists to survey the burgeoning octopus population.