2025 Proclaimed the 'Year of the Octopus' Off Britain's Southern Shores.

Exceptionally high observations of a remarkably clever cephalopod over the summer months have prompted the naming of 2025 as the octopus's year in a seasonal assessment of Britain’s seas.

Ideal Conditions Leading to an Explosion

A mild winter followed by an exceptionally warm spring prompted a huge population of Mediterranean octopuses to settle along the shores from Cornwall to Devon, spanning the Cornish and Devonian coasts.

“The scale of the catch was approximately thirteen times what we would usually anticipate in Cornish waters,” commented an ocean conservation expert. “Based on the totals, approximately 233,000 octopuses were caught in British seas this year – which is a significant rise from historical averages.”

The Mediterranean octopus is found in these waters but typically so rare it is seldom observed. A population bloom is attributed to a combination of a mild winter and a warm breeding season. This perfect scenario meant increased juvenile survival, maybe aided by large numbers of other marine life noted in recent years.

A Rare Phenomenon

The last time, a population surge of this scale this significant was documented in 1950, with past documentation indicating the last bloom prior to that occurred in 1900.

The sheer quantity of octopuses meant they could be easily spotted in nearshore environments for the first time in recent history. Diver videos show octopuses being sociable – unlike their typical solitary behavior – and “walking” along the bottom on their tentacle tips. One creature was even seen investigating an underwater camera.

“On my initial dive in that area this year I saw multiple octopuses,” they noted. “And these are big. We have two species in these waters. One species is smaller, about the size of a football, but these common octopuses can be with a span of 1.5 meters.”

Future Prospects and Other Surprises

Another mild winter this coming winter meant it was possible a repeat event next year, because historically, under these conditions, the blooms have repeated for two years running.

“However, it is unlikely, looking at history, that it will go on for a long time,” they cautioned. “But the sea keeps giving us surprises currently so it’s a very uncertain scenario.”

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

• Highest-ever counts of gray seals observed in Cumbria.
• Exceptional populations 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 type of blenny spotted off the coast of a southern county for the first time.

Environmental Concerns

Challenges were also present, however. “The calendar year was marked by environmental disasters,” said a head of marine conservation. “A major tanker collision in the North Sea and an accidental discharge of tonnes of plastic biobeads off the Sussex coast served as stark reminders. Conservation teams are putting in immense work to protect and restore our shorelines.”