2025 Hailed as 'The Octopus Year' Along Britain's South Coast.
Exceptionally high observations of a remarkably clever cephalopod this past summer have prompted the declaration of 2025 as the octopus's year in a seasonal assessment of Britain’s seas.
A Perfect Storm for a Population Boom
An unusually warm winter and then a remarkably hot spring triggered a huge population of Mediterranean octopuses to settle along the shores from Cornwall to Devon, across the southwestern peninsula.
“The volume of octopuses caught was of the order of about over a dozen times what we would normally expect in Cornish waters,” stated a marine conservation officer. “Calculating the figures, approximately 233,000 octopuses were present in these waters this year – representing a massive jump from historical averages.”
The common octopus is indigenous to UK waters but ordinarily in such small numbers it is seldom observed. A sudden increase is attributed to the dual effect of gentle winter conditions and favorable spring temperatures. Such favorable circumstances meant increased juvenile survival, potentially supported by large numbers of spider crabs noted in recent years.
An Uncommon Occurrence
The last time, an octopus bloom comparable was documented in the mid-20th century, with archival data indicating the previous major event was in 1900.
The remarkable abundance of octopuses meant they could be readily observed in shallow waters for the first time in recent history. Underwater recordings show octopuses gathering in groups – they are usually solitary – and moving along the bottom on their arm ends. One individual was even filmed grabbing a diver's camera.
“The first time I dived there this year I saw multiple octopuses,” the specialist continued. “They are large specimens. There are two types in these waters. The curled octopus is rather small, the size of a ball, but these common octopuses can be with a span of 1.5 meters.”
Looking Ahead & Coastal Highlights
If conditions remain mild this coming winter suggests the potential a repeat event in 2026, because in the past, under these conditions, events have occurred consecutively for two consecutive years.
“But, it's improbable, from previous blooms, that it will persist indefinitely,” they cautioned. “The ocean is full of surprises at the moment so it’s quite an unpredictable situation.”
The report also noted other “surprises, successes and joyful moments” along the coast, including:
- Highest-ever counts of grey seals seen in one northern region.
- Peak numbers of puffins on Skomer.
- The initial discovery of an unusual mollusc in a northern county, usually found in the south-west.
- A Mediterranean fish species found off the coast of a southern county for the inaugural time.
A Note of Caution
The year had its low points, however. “The year was bookended by ecological challenges,” said a head of marine conservation. “A significant shipping incident in March and a spill of industrial pellets off the southern coast were serious issues. Conservation teams are working tirelessly to protect and restore our shorelines.”