2025 Proclaimed the 'Year of the Octopus' Along Britain's Southern Shores.

Exceptionally high encounters of one of the world's most intelligent invertebrates this past summer have prompted the declaration of 2025 as “the year of the octopus” in an annual review of the nation's marine environment.

A Perfect Storm Leading to an Explosion

A gentle winter followed by a remarkably hot spring catalyzed unprecedented numbers of Mediterranean octopuses to settle along the shores from Cornwall to Devon, spanning the Cornish and Devonian coasts.

“The scale of the catch was approximately thirteen times what we would usually anticipate in the waters around Cornwall,” commented a marine conservation officer. “Calculating the figures, around 233 thousand octopuses were found in these waters this year – which is a significant rise from the norm.”

The common octopus is indigenous to UK waters but ordinarily in such small numbers it is rarely seen. A population bloom is attributed to the dual effect of gentle winter conditions and favorable spring temperatures. Such favorable circumstances meant more larvae, potentially supported by significant populations of a favored prey species also recorded.

A Rare Phenomenon

The most recent occasion, a population surge of this scale this significant was documented in the mid-20th century, with historical records indicating the last bloom prior to that occurred in 1900.

The huge numbers of octopuses meant they could be readily observed in nearshore environments for a rare occurrence. Diver videos show octopuses congregating together – unlike their typical solitary behavior – and moving along the bottom on their tentacle tips. One individual was even filmed grabbing an underwater camera.

“On my initial dive in that area this year I saw multiple octopuses,” the specialist continued. “They are large specimens. We have two species in UK waters. One species is quite small, football-sized, but these common octopuses can be reaching impressive sizes.”

Predictions and Marine Joy

Another mild winter this coming winter meant it was possible a repeat event in 2026, because in the past, under these conditions, events have occurred consecutively for two years in a row.

“Still, the chances are low, based on past events, that it will persist indefinitely,” they stated. “The ocean is full of surprises currently so it’s hard to forecast.”

The annual review also celebrated further encouraging coastal sightings across British shores, including:

• Highest-ever counts of grey seals seen in one northern region.
• Peak numbers of puffins on an island off Wales.
• A first-ever sighting of the *Capellinia fustifera* nudibranch in a northern county, usually found in the south-west.
• A Mediterranean fish species found off the coast of Sussex for the first time.

A Note of Caution

Challenges were also present, however. “The period was framed by ecological challenges,” stated an expert. “A significant shipping incident in the North Sea and a spill of plastic pollution off the southern coast were serious issues. Conservation teams are making huge efforts to defend and heal our marine habitats.”