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

Record-breaking sightings of a remarkably clever cephalopod over the summer months have led to the designation of 2025 as the octopus's year in a yearly report of UK coastal waters.

Ideal Conditions for a Population Boom

A gentle winter followed by an exceptionally warm spring triggered unprecedented numbers of common octopuses (*Octopus vulgaris*) to take up residence along England’s south coast, spanning the Cornish and Devonian coasts.

“The scale of the catch was approximately over a dozen times what we would usually anticipate in the waters around Cornwall,” explained a marine conservation officer. “When we added up the numbers, around 233 thousand octopuses were present in UK waters this year – which is a significant rise from the norm.”

The common octopus is native to these waters but typically so rare it is rarely seen. A sudden increase is the result of the dual effect of gentle winter conditions and a warm breeding season. This perfect scenario meant increased juvenile survival, maybe aided by large numbers of spider crabs noted in recent years.

A Rare Phenomenon

Previously, a population surge of this scale this significant was documented in the 1950s, with past documentation indicating the last bloom prior to that happened in 1900.

The huge numbers of octopuses meant they could be readily observed in coastal areas for the first time in living memory. Underwater recordings show octopuses being sociable – contrary to their normally lone nature – and moving along the ocean floor on the tips of their limbs. A curious octopus was even filmed grabbing an underwater camera.

“The first time I dived there this year I saw multiple octopuses,” they noted. “And these are big. There are two types 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 could lead to a repeat event next year, because based on records, under these conditions, the blooms have repeated for two years in a row.

“Still, the chances are low, from previous blooms, that it will become a permanent fixture,” they said. “Marine life is unpredictable at the moment so it’s quite an unpredictable situation.”

The report also noted further encouraging coastal sightings along the coast, including:

• Highest-ever counts of gray seals observed in Cumbria.
• Exceptional populations of puffins on a Welsh island.
• The initial discovery of a rare sea slug in Yorkshire, usually found in the south-west.
• A variable blenny spotted off the coast of Sussex for the inaugural time.

Not All Positive News

The year had its low points, however. “The year was bookended by ecological challenges,” noted a conservation leader. “A major tanker collision in March and the release of industrial pellets off the southern coast highlighted ongoing threats. Staff and volunteers are working tirelessly to protect and restore our shorelines.”