2025 Declared 'The Octopus Year' Off England's South Coast.

Unprecedented observations of one of the world's most intelligent invertebrates over the summer months have resulted in the designation of 2025 as “the year of the octopus” in an annual review of UK coastal waters.

Ideal Conditions Leading to an Explosion

An unusually warm winter coupled with an exceptionally warm spring prompted unprecedented numbers of Mediterranean octopuses to take up residence along the southern coastline of England, spanning the Cornish and Devonian coasts.

“The reported landings was approximately over a dozen times what we would usually anticipate in this region,” explained an ocean conservation expert. “Based on the totals, around 233 thousand octopuses were caught in UK waters this year – which is a significant rise from the norm.”

The common octopus is native to UK waters but ordinarily in such small numbers it is infrequently encountered. An explosive growth is caused by the dual effect of gentle winter conditions and a warm breeding season. Such favorable circumstances meant increased juvenile survival, possibly in part fuelled by large numbers of spider crabs also recorded.

An Uncommon Occurrence

The most recent occasion, an octopus bloom of this size was recorded in the mid-20th century, with past documentation indicating the one before that was in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be easily spotted in coastal areas for the first time in recent history. Underwater recordings show octopuses gathering in groups – they are usually solitary – and ambulating along the seabed on the tips of their limbs. One creature was even seen investigating an underwater camera.

“On my initial dive off the Lizard peninsula this year I saw multiple octopuses,” the specialist continued. “They are sizeable. Two kinds exist in UK waters. One species is rather small, about the size of a football, but these common octopuses can be reaching impressive sizes.”

Future Prospects and Other Surprises

If conditions remain mild this coming winter could lead to a second bloom in 2026, because historically, in similar situations, the blooms have repeated for two years in a row.

“However, it is unlikely, based on past events, that it will go on for a long time,” they said. “But the sea keeps giving us surprises currently so it’s quite an unpredictable situation.”

The annual review also noted other “surprises, successes and joyful moments” across British shores, including:

• A record number of grey seals recorded in Cumbria.
• Exceptional populations of the iconic seabirds on an island off Wales.
• A first-ever sighting of the *Capellinia fustifera* nudibranch in a northern county, normally residing farther south.
• A variable blenny spotted off the coast of Sussex for the first time.

Not All Positive News

Not everything was good news, however. “The period was framed by environmental disasters,” said a head of marine conservation. “A major tanker collision in March and an accidental discharge of tonnes of plastic biobeads off the Sussex coast were serious issues. Dedicated individuals are putting in immense work to protect and restore our shorelines.”