2025 Declared the 'Year of the Octopus' Off England's South Coast.

Unprecedented observations of a remarkably clever cephalopod this past summer have prompted the designation of 2025 as the octopus's year in an annual review of Britain’s seas.

A Confluence of Factors Leading to an Explosion

A gentle winter followed by an exceptionally warm spring triggered a huge population of Mediterranean octopuses to settle along England’s south coast, spanning the Cornish and Devonian coasts.

“The reported landings was approximately 13 times what we would typically see in this region,” stated an ocean conservation expert. “When we added up the numbers, around 233 thousand octopuses were found in these waters this year – which is a significant rise from the norm.”

The Mediterranean octopus is indigenous to UK waters but ordinarily in such small numbers it is rarely seen. A population bloom is attributed to a combination of gentle winter conditions and a warm breeding season. This perfect scenario meant a higher survival rate for young, potentially supported by large numbers of spider crabs seen in the area.

A Rare Phenomenon

Previously, an octopus bloom of this size was documented in the mid-20th century, with archival data indicating the one before that was in 1900.

The remarkable abundance of octopuses meant they could be readily observed in nearshore environments for the first time in living memory. Video footage show octopuses congregating together – contrary to their normally lone nature – and ambulating along the bottom on their arm ends. A curious octopus was even seen investigating an underwater camera.

“The first time I dived off the Lizard peninsula this year I saw multiple octopuses,” they noted. “They are large specimens. There are two types in UK waters. One species is quite small, about the size of a football, but these newcomers can be reaching impressive sizes.”

Predictions and Marine Joy

A second gentle winter going into 2026 suggests the potential another surge next year, because in the past, under these conditions, the blooms have repeated for two years running.

“Still, the chances are low, from previous blooms, that it will go on for a long time,” they cautioned. “The ocean is full of surprises these days so it’s a very uncertain scenario.”

The assessment also highlighted additional positive marine news across British shores, including:

• Unprecedented numbers of grey seals recorded in Cumbria.
• Peak numbers of the iconic seabirds on a Welsh island.
• The initial discovery of the *Capellinia fustifera* nudibranch in a northern county, normally residing farther south.
• A variable blenny found off the coast of Sussex for the inaugural time.

Environmental Concerns

The year had its low points, however. “The year was bookended by ecological challenges,” noted a conservation leader. “A significant shipping incident in March and the release of tonnes of plastic biobeads off the Sussex coast served as stark reminders. Conservation teams are putting in immense work to defend and heal our shorelines.”