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

Record-breaking encounters of one of the world's most intelligent invertebrates this past summer have led to the naming of 2025 as the year for octopuses in an annual review of Britain’s seas.

A Confluence of Factors Driving a Surge

A mild winter followed by a remarkably hot spring triggered a huge population 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 thirteen times what we would usually anticipate in the waters around Cornwall,” commented an ocean conservation expert. “Calculating the figures, approximately 233,000 octopuses were present in these waters this year – which is a significant rise from the norm.”

The Mediterranean octopus is native to British seas but ordinarily in such small numbers it is rarely seen. A population bloom is caused by a combination of gentle winter conditions and favorable spring temperatures. Such favorable circumstances meant more larvae, maybe aided by significant populations of spider crabs seen in the area.

A Historic Event

The last time, an octopus bloom comparable was observed in the 1950s, with archival data indicating the previous major event happened in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be easily spotted in shallow waters for a rare occurrence. Underwater recordings show octopuses congregating together – they are usually solitary – and moving along the bottom on their arm ends. One individual was even recorded reaching for an underwater camera.

“During a first dive in that area this year I saw multiple octopuses,” they noted. “They are sizeable. There are two types in the region. The curled octopus is rather small, the size of a ball, but the *Octopus vulgaris* can be with a span of 1.5 meters.”

Looking Ahead & Coastal Highlights

If conditions remain mild heading into next year meant it was possible a repeat event next year, because based on records, in similar situations, populations have surged again for two years running.

“However, it is unlikely, looking at history, that it will go on for a long time,” they cautioned. “But the sea keeps giving us surprises at the moment so it’s quite an unpredictable situation.”

The annual review also highlighted additional positive marine news along the coast, including:

• Highest-ever counts of grey seals seen in Cumbria.
• Record numbers of puffins on a Welsh island.
• The initial discovery of an unusual mollusc in a northern county, normally residing farther south.
• A Mediterranean fish species discovered off the coast of Sussex for the first time.

A Note of Caution

Challenges were also present, however. “The year was bookended by ecological challenges,” said a head of marine conservation. “A significant shipping incident in the North Sea and a spill of industrial pellets off the southern coast were serious issues. Staff and volunteers are working tirelessly to safeguard and rehabilitate our shorelines.”