2025 Declared The Year for Octopuses Along Britain's South Coast.

Unprecedented observations of a supremely intelligent sea creature over the summer months have led to the designation of 2025 as the octopus's year in an annual review of Britain’s seas.

A Confluence of Factors Leading to an Explosion

A gentle winter and then an exceptionally warm spring prompted unprecedented numbers of *Octopus vulgaris* to establish themselves along England’s south coast, across the southwestern peninsula.

“The volume of octopuses caught was roughly 13 times what we would normally expect in this region,” stated an ocean conservation expert. “When we added up the numbers, around 233 thousand octopuses were present in these waters this year – representing a massive jump from the norm.”

The Mediterranean octopus is found in these waters but typically so rare it is seldom observed. A sudden increase is caused by the dual effect of a mild winter and favorable spring temperatures. Such favorable circumstances meant a higher survival rate for young, possibly in part fuelled by significant populations of spider crabs noted in recent years.

A Historic Event

The most recent occasion, a population surge of this scale comparable was observed in the mid-20th century, with historical records indicating the last bloom prior to that happened in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be readily observed in nearshore environments for the first time in recent history. Diver videos show octopuses congregating together – contrary to their normally lone nature – and “walking” along the seabed on their tentacle tips. One individual was even seen investigating submarine recording equipment.

“The first time I dived off the Lizard peninsula this year I saw multiple octopuses,” the officer added. “And these are big. We have two species in UK waters. One species is quite small, the size of a ball, but these common octopuses can be up to a metre and a half wide.”

Future Prospects and Other Surprises

If conditions remain mild going into 2026 meant it was possible a repeat event in 2026, because based on records, under these conditions, the blooms have repeated for two years in a row.

“Still, the chances are low, looking at history, that it will persist indefinitely,” they cautioned. “Marine life is unpredictable at the moment so it’s hard to forecast.”

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

• Highest-ever counts of gray seals seen in Cumbria.
• Peak numbers of the iconic seabirds on a Welsh island.
• The initial discovery of a rare sea slug in Yorkshire, usually found in the south-west.
• A Mediterranean fish species found off the coast of a southern county for the first occasion.

A Note of Caution

Not everything was good news, however. “The period was framed by ecological challenges,” noted a conservation leader. “A major tanker collision in the North Sea and the release of tonnes of plastic biobeads off the Sussex coast highlighted ongoing threats. Staff and volunteers are putting in immense work to safeguard and rehabilitate our shorelines.”