2025 Hailed as the 'Year of the Octopus' Off Britain's South Coast.
Unprecedented encounters of a supremely intelligent sea creature over the summer months have resulted in the designation of 2025 as the year for octopuses in a yearly report of UK coastal waters.
Ideal Conditions Driving a Surge
An unusually warm winter coupled with a very warm springtime prompted a massive influx of Mediterranean octopuses to settle along England’s south coast, from Penzance in Cornwall to south Devon.
“The volume of octopuses caught was of the order of about over a dozen times what we would normally expect in Cornish waters,” explained an ocean conservation expert. “When we added up the numbers, nearly a quarter of a million octopuses were present in UK waters this year – representing a massive jump from the norm.”
The Mediterranean octopus is indigenous to these waters but usually so scarce it is infrequently encountered. A population bloom is the result of a combination of a mild winter and a warm breeding season. This perfect scenario meant more larvae, maybe aided by large numbers of spider crabs seen in the area.
A Rare Phenomenon
The last time, an octopus bloom comparable was recorded in 1950, with archival data indicating the last bloom prior to that happened in the turn of the 20th century.
The remarkable abundance of octopuses meant they could be readily observed in nearshore environments for a rare occurrence. Diver videos show octopuses congregating together – contrary to their normally lone nature – and “walking” along the seabed on their arm ends. One creature was even recorded reaching for an underwater camera.
“The first time I dived in that area this year I saw multiple octopuses,” they noted. “They are large specimens. We have two species in these waters. One species is quite small, the size of a ball, but these newcomers can be reaching impressive sizes.”
Predictions and Marine Joy
If conditions remain mild this coming winter meant it was possible a second bloom the following year, because historically, with such patterns, populations have surged again for two years running.
“But, it's improbable, based on past events, that it will go on for a long time,” they said. “But the sea keeps giving us surprises at the moment so it’s quite an unpredictable situation.”
The annual review also noted additional positive marine news around the UK coastline, including:
- Highest-ever counts of grey seals observed in one northern region.
- Record numbers of the iconic seabirds on an island off Wales.
- The first recording of a rare sea slug in Yorkshire, normally residing farther south.
- A variable blenny discovered off the coast of a southern county for the inaugural time.
Not All Positive News
Challenges were also present, however. “The period was framed by marine incidents,” said a head of marine conservation. “A major tanker collision in March and the release of tonnes of plastic biobeads off the southern coast served as stark reminders. Dedicated individuals are working tirelessly to safeguard and rehabilitate our coasts.”