2025 Declared 'The Octopus Year' Off Britain's South Coast.

Record-breaking encounters of a remarkably clever cephalopod this past summer have resulted in the designation of 2025 as “the year of the octopus” in an annual review of Britain’s seas.

Ideal Conditions Leading to an Explosion

A mild winter and then an exceptionally warm spring prompted unprecedented numbers of common octopuses (*Octopus vulgaris*) to settle along the southern coastline of England, spanning the Cornish and Devonian coasts.

“The volume of octopuses caught was roughly thirteen times what we would typically see in Cornish waters,” stated a marine conservation officer. “Calculating the figures, approximately 233,000 octopuses were caught in UK waters this year – which is a significant rise from historical averages.”

*Octopus vulgaris* is found in these waters but ordinarily in such small numbers it is seldom observed. An explosive growth is attributed to a combination of a mild winter and a warm breeding season. This perfect scenario meant a higher survival rate for young, potentially supported by abundant stocks of other marine life also recorded.

A Historic Event

The last time, a population surge of this scale comparable was observed in the 1950s, with past documentation indicating the one before that happened in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be easily spotted in nearshore environments for the first time in recent history. Underwater recordings show octopuses congregating together – they are usually solitary – and moving along the ocean floor on their tentacle tips. A curious octopus was even seen investigating an underwater camera.

“The first time I dived off the Lizard peninsula this year I saw five of these creatures,” they noted. “And these are big. We have two species in these waters. One species is quite small, about the size of a football, but these newcomers can be up to a metre and a half wide.”

Predictions and Marine Joy

If conditions remain mild going into 2026 could lead to a second bloom in 2026, because in the past, under these conditions, events have occurred consecutively for two years running.

“But, it's improbable, looking at history, that it will persist indefinitely,” they cautioned. “The ocean is full of surprises these days so it’s a very uncertain scenario.”

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

• Unprecedented numbers of grey seals seen in one northern region.
• Record numbers of puffins on an island off Wales.
• A first-ever sighting of a rare sea slug in Yorkshire, usually found in the south-west.
• A variable blenny spotted off the coast of a southern county for the first occasion.

Not All Positive News

The year had its low points, however. “The calendar year was marked by ecological challenges,” noted a conservation leader. “A major tanker collision in the North Sea and the release of plastic pollution off the Sussex coast were serious issues. Conservation teams are working tirelessly to protect and restore our marine habitats.”