Record-breaking sightings of one of the world's most intelligent invertebrates this past summer have led to the declaration of 2025 as the year for octopuses in an annual review of UK coastal waters.
A Perfect Storm Leading to an Explosion
A gentle winter coupled with an exceptionally warm spring prompted unprecedented numbers of common octopuses (*Octopus vulgaris*) to settle along England’s south coast, spanning the Cornish and Devonian coasts.
“The volume of octopuses caught was of the order of about over a dozen times what we would typically see in Cornish waters,” explained an ocean conservation expert. “When we added up the numbers, around 233 thousand octopuses were caught in British seas this year – that’s a huge increase from the norm.”
*Octopus vulgaris* is native to British seas but ordinarily in such small numbers it is infrequently encountered. A sudden increase is caused by a combination of a mild winter and favorable spring temperatures. This perfect scenario meant a higher survival rate for young, potentially supported by significant populations of spider crabs seen in the area.
A Rare Phenomenon
Previously, such an octopus proliferation of this size was recorded in 1950, with archival data indicating the previous major event was in 1900.
The sheer quantity of octopuses meant they could be frequently seen in shallow waters for a rare occurrence. Video footage show octopuses gathering in groups – contrary to their normally lone nature – and moving along the ocean floor on their tentacle tips. A curious octopus was even seen investigating an underwater camera.
“On my initial dive off the Lizard peninsula this year I saw five octopuses,” they noted. “They are large specimens. We have two species in these waters. The curled octopus is smaller, football-sized, but these common octopuses can be with a span of 1.5 meters.”
Future Prospects and Other Surprises
A second gentle winter going into 2026 suggests the potential a repeat event next year, because historically, with such patterns, events have occurred consecutively for two years running.
“But, it's improbable, based on past events, that it will go on for a long time,” they cautioned. “The ocean is full of surprises currently so it’s quite an unpredictable situation.”
The report also highlighted additional positive marine news along the coast, including:
- Highest-ever counts of grey seals recorded in Cumbria.
- Record numbers of puffins on Skomer.
- A first-ever sighting of an unusual mollusc in Yorkshire, typically a southwestern species.
- A Mediterranean fish species found off the coast of Sussex for the first time.
Environmental Concerns
Challenges were also present, however. “The period was framed by environmental disasters,” noted a conservation leader. “A significant shipping incident in March and a spill of industrial pellets off the Sussex coast served as stark reminders. Staff and volunteers are putting in immense work to protect and restore our marine habitats.”
