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

Unprecedented sightings of a remarkably clever cephalopod this past summer have resulted in the naming of 2025 as “the year of the octopus” in an annual review of Britain’s seas.

Ideal Conditions for a Population Boom

An unusually warm winter coupled with a remarkably hot spring prompted a huge population of Mediterranean octopuses to settle along the shores from Cornwall to Devon, across the southwestern peninsula.

“The scale of the catch was of the order of about over a dozen times what we would usually anticipate in this region,” commented a marine conservation officer. “Based on the totals, approximately 233,000 octopuses were found in these waters this year – that’s a huge increase from the norm.”

*Octopus vulgaris* is indigenous to British seas but typically so rare it is seldom observed. A sudden increase is the result of the dual effect of gentle winter conditions and a warm breeding season. This perfect scenario meant a higher survival rate for young, possibly in part fuelled by abundant stocks of spider crabs also recorded.

An Uncommon Occurrence

Previously, an octopus bloom of this size was observed in 1950, with historical records indicating the last bloom prior to that happened in 1900.

The remarkable abundance of octopuses meant they could be easily spotted in nearshore environments for a rare occurrence. Diver videos show octopuses congregating together – unlike their typical solitary behavior – and ambulating along the bottom on their tentacle tips. A curious octopus was even filmed grabbing submarine recording equipment.

“The first time I dived there this year I saw five of these creatures,” the specialist continued. “They are sizeable. There are two types in these waters. The curled octopus is rather small, the size of a ball, but these newcomers can be up to a metre and a half wide.”

Looking Ahead & Coastal Highlights

If conditions remain mild going into 2026 could lead to a second bloom the following year, because based on records, in similar situations, the blooms have repeated for two years in a row.

“But, it's improbable, looking at history, that it will go on for a long time,” they cautioned. “The ocean is full of surprises currently so it’s hard to forecast.”

The annual review also noted additional positive marine news along the coast, including:

• A record number of grey seals seen in Cumbria.
• Record numbers of the iconic seabirds on Skomer.
• The first recording of an unusual mollusc in Yorkshire, typically a southwestern species.
• A variable blenny discovered off the coast of a southern county for the inaugural time.

A Note of Caution

Not everything was good news, however. “The calendar year was marked by ecological challenges,” said a head of marine conservation. “A major tanker collision in the North Sea and an accidental discharge of plastic pollution off the Sussex coast served as stark reminders. Dedicated individuals are putting in immense work to protect and restore our coasts.”