2025 Declared The Year for Octopuses Off Britain's Southern Shores.

Exceptionally high observations of one of the world's most intelligent invertebrates during the summer season have led to the designation of 2025 as the octopus's year in an annual review of Britain’s seas.

A Confluence of Factors for a Population Boom

An unusually warm winter and then a very warm springtime catalyzed a huge population of common octopuses (*Octopus vulgaris*) to establish themselves along the southern coastline of England, across the southwestern peninsula.

“The volume of octopuses caught was roughly 13 times what we would normally expect in the waters around Cornwall,” explained a marine life specialist. “Based on the totals, nearly a quarter of a million octopuses were present in British seas this year – which is a significant rise from the norm.”

The Mediterranean octopus is native to these waters but typically so rare it is seldom observed. A sudden increase is caused by a combination of gentle winter conditions and favorable spring temperatures. This perfect scenario meant more larvae, possibly in part fuelled by significant populations of a favored prey species also recorded.

An Uncommon Occurrence

Previously, a population surge of this scale comparable was observed in 1950, with archival data indicating the last bloom prior to that was in 1900.

The huge numbers of octopuses meant they could be easily spotted in coastal areas for the first time in recent history. Video footage show octopuses gathering in groups – they are usually solitary – and ambulating along the ocean floor on their tentacle tips. One individual was even filmed grabbing an underwater camera.

“During a first dive off the Lizard peninsula this year I saw five of these creatures,” they noted. “They are sizeable. There are two types in these waters. One species is quite small, the size of a ball, but the *Octopus vulgaris* can be reaching impressive sizes.”

Predictions and Marine Joy

Another mild winter going into 2026 meant it was possible a repeat event next year, because based on records, under these conditions, the blooms have repeated for two years running.

“However, it is unlikely, looking at history, that it will persist indefinitely,” they cautioned. “Marine life is unpredictable these days so it’s hard to forecast.”

The report also highlighted additional positive marine news along the coast, including:

• Unprecedented numbers of gray seals observed in one northern region.
• Peak numbers of puffins on an island off Wales.
• The first recording of a rare sea slug in a northern county, normally residing farther south.
• A variable blenny found off the coast of a southern county for the inaugural time.

Not All Positive News

Challenges were also present, however. “The year was bookended by marine incidents,” said a head of marine conservation. “A major tanker collision in March and a spill of tonnes of plastic biobeads off the Sussex coast were serious issues. Staff and volunteers are working tirelessly to defend and heal our shorelines.”