2025 Declared The Year for Octopuses Off England's South Coast.

Exceptionally high encounters of one of the world's most intelligent invertebrates over the summer months have prompted the naming of 2025 as “the year of the octopus” in a seasonal assessment of the nation's marine environment.

A Perfect Storm Driving a Surge

An unusually warm winter followed by a very warm springtime triggered a huge population of common octopuses (*Octopus vulgaris*) to establish themselves along the shores from Cornwall to Devon, spanning the Cornish and Devonian coasts.

“The reported landings was of the order of about 13 times what we would normally expect in Cornish waters,” explained an ocean conservation expert. “When we added up the numbers, approximately 233,000 octopuses were caught in these waters this year – that’s a huge increase from historical averages.”

*Octopus vulgaris* is found in these waters but typically so rare it is infrequently encountered. An explosive growth is attributed to the dual effect of gentle winter conditions and a warm breeding season. This perfect scenario meant increased juvenile survival, maybe aided by significant populations of other marine life seen in the area.

A Rare Phenomenon

The most recent occasion, a population surge of this scale of this size was documented in the 1950s, with past documentation indicating the last bloom prior to that happened in 1900.

The sheer quantity of octopuses meant they could be readily observed in coastal areas for the first time in living memory. Diver videos show octopuses being sociable – unlike their typical solitary behavior – and “walking” along the ocean floor on their arm ends. One individual was even filmed grabbing submarine recording equipment.

“The first time I dived in that area this year I saw five of these creatures,” the specialist continued. “They are large specimens. Two kinds exist in these waters. The curled octopus is smaller, the size of a ball, but these newcomers can be up to a metre and a half wide.”

Looking Ahead & Coastal Highlights

A second gentle winter going into 2026 suggests the potential a repeat event the following year, because based on records, in similar situations, populations have surged again for two years running.

“However, it is unlikely, looking at history, that it will become a permanent fixture,” they cautioned. “The ocean is full of surprises these days so it’s quite an unpredictable situation.”

The annual review also celebrated other “surprises, successes and joyful moments” along the coast, including:

• Unprecedented numbers of grey seals observed in Cumbria.
• Peak numbers of puffins on an island off Wales.
• The initial discovery of the *Capellinia fustifera* nudibranch in Yorkshire, normally residing farther south.
• A Mediterranean fish species discovered off the coast of Sussex for the inaugural time.

Not All Positive News

Challenges were also present, however. “The year was bookended by ecological challenges,” stated an expert. “A significant shipping incident in the North Sea and an accidental discharge of industrial pellets off the Sussex coast served as stark reminders. Dedicated individuals are making huge efforts to protect and restore our marine habitats.”