2025 Proclaimed 'The Octopus Year' Off England's Southern Shores.

Record-breaking observations of one of the world's most intelligent invertebrates this past summer have prompted the designation of 2025 as the year for octopuses in a yearly report of the nation's marine environment.

A Confluence of Factors Driving a Surge

A mild winter coupled with a remarkably hot spring prompted unprecedented numbers of Mediterranean octopuses to settle 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 typically see in Cornish waters,” explained an ocean conservation expert. “Calculating the figures, approximately 233,000 octopuses were caught in UK waters this year – representing a massive jump from historical averages.”

The common octopus is native to these waters but ordinarily in such small numbers it is infrequently encountered. An explosive growth is attributed to a combination of a mild winter and favorable spring temperatures. Such favorable circumstances meant increased juvenile survival, possibly in part fuelled by large numbers of a favored prey species seen in the area.

An Uncommon Occurrence

Previously, a population surge of this scale this significant was recorded in the 1950s, with past documentation indicating the previous major event happened in 1900.

The huge numbers of octopuses meant they could be readily observed in nearshore environments for the first time in recent history. Underwater recordings show octopuses congregating together – contrary to their normally lone nature – and moving along the seabed on their tentacle tips. A curious octopus was even filmed grabbing submarine recording equipment.

“On my initial dive off the Lizard peninsula this year I saw multiple octopuses,” the officer added. “And these are big. We have two species in UK waters. The curled octopus is quite small, the size of a ball, but these common octopuses can be reaching impressive sizes.”

Predictions and Marine Joy

If conditions remain mild going into 2026 suggests the potential a repeat event next year, because in the past, with such patterns, events have occurred consecutively for two years in a row.

“But, it's improbable, from previous blooms, that it will become a permanent fixture,” they stated. “The ocean is full of surprises at the moment so it’s quite an unpredictable situation.”

The report also highlighted other “surprises, successes and joyful moments” around the UK coastline, including:

• A record number of gray seals recorded in one northern region.
• Record numbers of the iconic seabirds on a Welsh island.
• A first-ever sighting of a rare sea slug in a northern county, normally residing farther south.
• A variable blenny discovered off the coast of Sussex for the first time.

A Note of Caution

The year had its low points, however. “The year was bookended by marine incidents,” stated an expert. “A major tanker collision in March and an accidental discharge of tonnes of plastic biobeads off the southern coast highlighted ongoing threats. Dedicated individuals are putting in immense work to defend and heal our shorelines.”