2025 Hailed as The Year for Octopuses Off Britain's Southern Shores.
Exceptionally high encounters of one of the world's most intelligent invertebrates this past summer have resulted in the declaration of 2025 as the octopus's year in an annual review of Britain’s seas.
Ideal Conditions for a Population Boom
A gentle winter and then a remarkably hot spring prompted a huge population of Mediterranean octopuses to settle along the shores from Cornwall to Devon, across the southwestern peninsula.
“The reported landings was roughly thirteen times what we would typically see in Cornish waters,” explained an ocean conservation expert. “Based on the totals, nearly a quarter of a million octopuses were present in British seas this year – representing a massive jump from what is typical.”
The common octopus is native to these waters but ordinarily in such small numbers it is infrequently encountered. A sudden increase is caused by the dual effect of gentle winter conditions and favorable spring temperatures. This perfect scenario meant more larvae, potentially supported by large numbers of spider crabs also recorded.
A Rare Phenomenon
The last time, a population surge of this scale comparable was recorded in 1950, with historical records indicating the previous major event was in the turn of the 20th century.
The remarkable abundance of octopuses meant they could be easily spotted in nearshore environments for the first time in recent history. Video footage show octopuses being sociable – unlike their typical solitary behavior – and “walking” along the ocean floor on their tentacle tips. One individual was even filmed grabbing an underwater camera.
“During a first dive off the Lizard peninsula this year I saw five of these creatures,” the specialist continued. “They are large specimens. There are two types in these waters. The curled octopus is quite small, the size of a ball, but these newcomers can be with a span of 1.5 meters.”
Future Prospects and Other Surprises
Another mild winter this coming winter meant it was possible a second bloom in 2026, because historically, under these conditions, populations have surged again for two years running.
“But, it's improbable, from previous blooms, that it will become a permanent fixture,” they said. “But the sea keeps giving us surprises at the moment so it’s hard to forecast.”
The annual review also highlighted additional positive marine news along the coast, including:
- Unprecedented numbers of grey seals observed in Cumbria.
- Exceptional populations of puffins on an island off Wales.
- The first recording of a rare sea slug in Yorkshire, usually found in the south-west.
- A Mediterranean fish species spotted off the coast of a southern county for the first occasion.
A Note of Caution
Challenges were also present, however. “The year was bookended by environmental disasters,” stated an expert. “A major tanker collision in March and a spill of industrial pellets off the southern coast served as stark reminders. Dedicated individuals are putting in immense work to protect and restore our shorelines.”