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

Record-breaking encounters of a remarkably clever cephalopod during the summer season have prompted the declaration of 2025 as the year for octopuses in an annual review of UK coastal waters.

Ideal Conditions Leading to an Explosion

An unusually warm winter coupled with a very warm springtime triggered a massive influx of Mediterranean octopuses to establish themselves along the shores from Cornwall to Devon, across the southwestern peninsula.

“The volume of octopuses caught was of the order of about thirteen times what we would usually anticipate in Cornish waters,” stated a marine conservation officer. “Based on the totals, nearly a quarter of a million octopuses were present in these waters this year – representing a massive jump from historical averages.”

The common octopus is found in UK waters but ordinarily in such small numbers it is seldom observed. A population bloom is caused by the dual effect of a mild winter and favorable spring temperatures. Such favorable circumstances meant more larvae, possibly in part fuelled by significant populations of a favored prey species seen in the area.

A Rare Phenomenon

The most recent occasion, such an octopus proliferation comparable was documented in the 1950s, with historical records indicating the previous major event happened in 1900.

The huge numbers of octopuses meant they could be easily spotted in nearshore environments for the first time in living memory. Video footage show octopuses congregating together – they are usually solitary – and “walking” along the seabed on the tips of their limbs. A curious octopus was even seen investigating submarine recording equipment.

“The first time I dived off the Lizard peninsula this year I saw five of these creatures,” they noted. “They are large specimens. Two kinds exist in these waters. One species is rather small, about the size of a football, but these common octopuses can be with a span of 1.5 meters.”

Looking Ahead & Coastal Highlights

Another mild winter going into 2026 meant it was possible another surge the following year, because based on records, in similar situations, the blooms have repeated for two years running.

“But, it's improbable, based on past events, that it will persist indefinitely,” they stated. “But the sea keeps giving us surprises these days so it’s quite an unpredictable situation.”

The report also noted other “surprises, successes and joyful moments” across British shores, including:

• A record number of grey seals seen in Cumbria.
• Exceptional populations of puffins on Skomer.
• The first recording of the *Capellinia fustifera* nudibranch in a northern county, normally residing farther south.
• A variable blenny spotted off the coast of Sussex for the inaugural time.

Not All Positive News

Not everything was good news, however. “The period was framed by environmental disasters,” stated an expert. “A significant shipping incident in March and a spill of industrial pellets off the Sussex coast were serious issues. Staff and volunteers are making huge efforts to defend and heal our shorelines.”