2025 Declared 'The Octopus Year' Off Britain's Southern Shores.

Unprecedented observations of a supremely intelligent sea creature this past summer have resulted in the designation of 2025 as the octopus's year in a yearly report of UK coastal waters.

Ideal Conditions Driving a Surge

A gentle winter and then a remarkably hot spring triggered a huge population of Mediterranean octopuses to settle along the southern coastline of England, from Penzance in Cornwall to south Devon.

“The volume of octopuses caught was approximately thirteen times what we would normally expect in the waters around Cornwall,” explained a marine life specialist. “Calculating the figures, around 233 thousand octopuses were caught in British seas this year – representing a massive jump from historical averages.”

The Mediterranean octopus is native to these waters but usually so scarce it is infrequently encountered. A sudden increase is the result of a combination of gentle winter conditions and a warm breeding season. This perfect scenario meant more larvae, possibly in part fuelled by large numbers of spider crabs noted in recent years.

A Historic Event

The last time, a population surge of this scale of this size was documented in the 1950s, with historical records indicating the previous major event happened in 1900.

The sheer quantity of octopuses meant they could be readily observed in shallow waters for the first time in living memory. Video footage show octopuses gathering in groups – they are usually solitary – and “walking” along the seabed on their tentacle tips. One creature was even seen investigating a diver's camera.

“The first time I dived off the Lizard peninsula this year I saw five of these creatures,” the officer added. “They are sizeable. Two kinds exist in UK waters. The curled octopus is smaller, the size of a ball, but the *Octopus vulgaris* can be up to a metre and a half wide.”

Future Prospects and Other Surprises

A second gentle winter going into 2026 meant it was possible a repeat event in 2026, because in the past, with such patterns, populations have surged again for two consecutive years.

“Still, the chances are low, based on past events, that it will become a permanent fixture,” they cautioned. “But the sea keeps giving us surprises currently so it’s hard to forecast.”

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

• Highest-ever counts of gray seals recorded in Cumbria.
• Exceptional populations of puffins on Skomer.
• The first recording of an unusual mollusc in a northern county, normally residing farther south.
• A variable blenny found off the coast of Sussex 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 March and a spill of tonnes of plastic biobeads off the Sussex coast served as stark reminders. Staff and volunteers are working tirelessly to safeguard and rehabilitate our shorelines.”