2025 Declared The Year for Octopuses Off England's South Coast.
Record-breaking encounters of one of the world's most intelligent invertebrates during the summer season have prompted the designation of 2025 as the year for octopuses in a yearly report of Britain’s seas.
Ideal Conditions Driving a Surge
A gentle winter coupled with an exceptionally warm spring triggered a massive influx of Mediterranean octopuses to establish themselves along the shores from Cornwall to Devon, spanning the Cornish and Devonian coasts.
“The scale of the catch was of the order of about 13 times what we would usually anticipate in Cornish waters,” explained an ocean conservation expert. “When we added up the numbers, approximately 233,000 octopuses were present in these waters this year – that’s a huge increase from the norm.”
*Octopus vulgaris* is found in British seas but ordinarily in such small numbers it is infrequently encountered. An explosive growth is caused by a combination of gentle winter conditions and favorable spring temperatures. Such favorable circumstances meant more larvae, potentially supported by large numbers of spider crabs noted in recent years.
A Historic Event
The most recent occasion, an octopus bloom of this size was observed in the mid-20th century, with past documentation indicating the last bloom prior to that occurred in 1900.
The huge numbers of octopuses meant they could be frequently seen in shallow waters for a rare occurrence. Video footage show octopuses gathering in groups – they are usually solitary – and moving along the ocean floor on their tentacle tips. A curious octopus was even recorded reaching for an underwater camera.
“On my initial dive there this year I saw five of these creatures,” they noted. “And these are big. Two kinds exist in these waters. One species is rather small, football-sized, but the *Octopus vulgaris* 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 next year, because historically, under these conditions, the blooms have repeated for two years in a row.
“But, it's improbable, from previous blooms, that it will persist indefinitely,” they cautioned. “But the sea keeps giving us surprises at the moment so it’s quite an unpredictable situation.”
The annual review also celebrated other “surprises, successes and joyful moments” across British shores, including:
- A record number of gray seals observed in one northern region.
- Exceptional populations of the iconic seabirds on Skomer.
- The initial discovery of the *Capellinia fustifera* nudibranch in a northern county, typically a southwestern species.
- A variable blenny discovered off the coast of Sussex for the first time.
Environmental Concerns
The year had its low points, however. “The year was bookended by environmental disasters,” said a head of marine conservation. “A significant shipping incident in March and the release of plastic pollution off the Sussex coast served as stark reminders. Dedicated individuals are putting in immense work to safeguard and rehabilitate our shorelines.”
