2025 Proclaimed 'The Octopus Year' Along Britain's South Coast.

Record-breaking sightings 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 UK coastal waters.

A Perfect Storm for a Population Boom

An unusually warm winter and then a very warm springtime triggered unprecedented numbers of common octopuses (*Octopus vulgaris*) to establish themselves along the shores from Cornwall to Devon, across the southwestern peninsula.

“The volume of octopuses caught was roughly 13 times what we would typically see in the waters around Cornwall,” explained an ocean conservation expert. “Calculating the figures, approximately 233,000 octopuses were found in these waters this year – representing a massive jump from the norm.”

The Mediterranean octopus is indigenous to British seas but ordinarily in such small numbers it is seldom observed. A population bloom is caused by a combination of gentle winter conditions and favorable spring temperatures. This perfect scenario meant more larvae, potentially supported by significant populations of spider crabs noted in recent years.

A Historic Event

The most recent occasion, such an octopus proliferation 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 easily spotted in nearshore environments for the first time in living memory. Diver videos show octopuses being sociable – they are usually solitary – and “walking” along the bottom on their tentacle tips. One individual was even filmed grabbing an underwater camera.

“During a first dive off the Lizard peninsula this year I saw five octopuses,” the officer added. “They are large specimens. We have two species in these waters. The curled octopus is smaller, about the size of a football, but the *Octopus vulgaris* can be with a span of 1.5 meters.”

Future Prospects and Other Surprises

A second gentle winter going into 2026 suggests the potential a repeat event next year, because historically, under these conditions, the blooms have repeated for two years running.

“However, it is unlikely, based on past events, that it will go on for a long time,” they said. “Marine life is unpredictable these days so it’s a very uncertain scenario.”

The report also celebrated additional positive marine news around the UK coastline, including:

• A record number of grey seals seen in one northern region.
• Peak numbers of puffins on a Welsh island.
• A first-ever sighting of the *Capellinia fustifera* nudibranch in a northern county, typically a southwestern species.
• A Mediterranean fish species found off the coast of a southern county for the first time.

Environmental Concerns

Challenges were also present, however. “The calendar year was marked by marine incidents,” stated an expert. “A significant shipping incident in the North Sea and a spill of tonnes of plastic biobeads off the southern coast served as stark reminders. Dedicated individuals are putting in immense work to safeguard and rehabilitate our coasts.”