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

Unprecedented encounters of one of the world's most intelligent invertebrates over the summer months have prompted the declaration of 2025 as “the year of the octopus” in an annual review of Britain’s seas.

A Confluence of Factors Leading to an Explosion

A gentle winter coupled with an exceptionally warm spring triggered a massive influx of Mediterranean octopuses to take up residence along the shores from Cornwall to Devon, from Penzance in Cornwall to south Devon.

“The scale of the catch was roughly thirteen times what we would usually anticipate in this region,” explained an ocean conservation expert. “Based on the totals, nearly a quarter of a million octopuses were caught in UK waters this year – representing a massive jump from what is typical.”

The common octopus is found in UK waters but typically so rare it is seldom observed. A sudden increase is caused by a combination of a mild winter and favorable spring temperatures. This perfect scenario meant increased juvenile survival, possibly in part fuelled by significant populations of spider crabs also recorded.

An Uncommon Occurrence

Previously, a population surge of this scale comparable was observed in the mid-20th century, with historical records indicating the previous major event was in 1900.

The sheer quantity of octopuses meant they could be readily observed in shallow waters for a rare occurrence. Underwater recordings show octopuses gathering in groups – contrary to their normally lone nature – and moving along the bottom on their arm ends. A curious octopus was even seen investigating submarine recording equipment.

“During a first dive there this year I saw five of these creatures,” the specialist continued. “And these are big. Two kinds exist in UK waters. One species is rather small, about the size of a football, but these newcomers can be up to a metre and a half wide.”

Looking Ahead & Coastal Highlights

If conditions remain mild heading into next year meant it was possible a second bloom the following year, because based on records, with such patterns, events have occurred consecutively for two consecutive years.

“However, it is unlikely, looking at history, that it will go on for a long time,” they said. “Marine life is unpredictable currently so it’s quite an unpredictable situation.”

The assessment also celebrated further encouraging coastal sightings around the UK coastline, including:

• Highest-ever counts of gray seals observed in one northern region.
• Peak numbers of puffins on an island off Wales.
• The first recording of the *Capellinia fustifera* nudibranch in Yorkshire, usually found in the south-west.
• A Mediterranean fish species discovered off the coast of a southern county for the first time.

Not All Positive News

The year had its low points, however. “The year was bookended by marine incidents,” said a head of marine conservation. “A significant shipping incident in March and the release of tonnes of plastic biobeads off the southern coast served as stark reminders. Dedicated individuals are making huge efforts to defend and heal our shorelines.”