2025 Proclaimed the 'Year of the Octopus' Off Britain's South Coast.

Unprecedented encounters of one of the world's most intelligent invertebrates this past summer have led to the naming of 2025 as the octopus's year in an annual review of UK coastal waters.

A Perfect Storm Leading to an Explosion

A mild winter coupled with a very warm springtime triggered unprecedented numbers of *Octopus vulgaris* to establish themselves along the shores from Cornwall to Devon, across the southwestern peninsula.

“The volume of octopuses caught was approximately thirteen times what we would usually anticipate in this region,” explained an ocean conservation expert. “When we added up the numbers, approximately 233,000 octopuses were found in UK waters this year – which is a significant rise from what is typical.”

*Octopus vulgaris* is found in UK waters but usually so scarce it is rarely seen. An explosive growth is attributed to a combination of a mild winter and favorable spring temperatures. Such favorable circumstances meant increased juvenile survival, maybe aided by large numbers of a favored prey species noted in recent years.

A Historic Event

The most recent occasion, an octopus bloom comparable was documented in the mid-20th century, with past documentation indicating the previous major event happened in 1900.

The sheer quantity of octopuses meant they could be frequently seen in nearshore environments for a rare occurrence. Diver videos show octopuses being sociable – unlike their typical solitary behavior – and moving along the bottom on their tentacle tips. One individual was even seen investigating a diver's camera.

“On my initial dive there this year I saw five of these creatures,” the specialist continued. “They are sizeable. There are two types in these waters. The curled octopus is rather small, the size of a ball, but these common octopuses can be with a span of 1.5 meters.”

Looking Ahead & Coastal Highlights

A second gentle winter going into 2026 meant it was possible a repeat event in 2026, because historically, with such patterns, events have occurred consecutively for two years in a row.

“However, it is unlikely, from previous blooms, that it will go on for a long time,” they cautioned. “But the sea keeps giving us surprises these days so it’s a very uncertain scenario.”

The annual review also celebrated further encouraging coastal sightings around the UK coastline, including:

• Unprecedented numbers of grey seals seen in one northern region.
• Exceptional populations of the iconic seabirds on an island off Wales.
• The first recording of the *Capellinia fustifera* nudibranch in Yorkshire, typically a southwestern species.
• A Mediterranean fish species found off the coast of Sussex for the inaugural time.

Not All Positive News

Not everything was good news, however. “The calendar year was marked by ecological challenges,” said a head of marine conservation. “A major tanker collision in March and an accidental discharge of plastic pollution off the southern coast were serious issues. Conservation teams are making huge efforts to defend and heal our shorelines.”