2025 Hailed as the 'Year of the Octopus' Off England's South Coast.

Exceptionally high observations of one of the world's most intelligent invertebrates during the summer season have led to the declaration of 2025 as the octopus's year in a yearly report of UK coastal waters.

Ideal Conditions for a Population Boom

A mild winter and then an exceptionally warm spring triggered a huge population of common octopuses (*Octopus vulgaris*) to take up residence along the shores from Cornwall to Devon, across the southwestern peninsula.

“The volume of octopuses caught was roughly over a dozen times what we would usually anticipate in Cornish waters,” stated an ocean conservation expert. “When we added up the numbers, around 233 thousand octopuses were found in British seas this year – that’s a huge increase from the norm.”

The Mediterranean octopus is found in UK waters but typically so rare it is seldom observed. An explosive growth is attributed to the dual effect of a mild winter and favorable spring temperatures. Such favorable circumstances meant increased juvenile survival, maybe aided by significant populations of other marine life noted in recent years.

A Rare Phenomenon

Previously, a population surge of this scale comparable was observed in the 1950s, with archival data indicating the last bloom prior to that was in the turn of the 20th century.

The huge numbers of octopuses meant they could be readily observed in nearshore environments for a rare occurrence. Underwater recordings show octopuses congregating together – contrary to their normally lone nature – and ambulating along the ocean floor on the tips of their limbs. A curious octopus was even seen investigating a diver's camera.

“The first time I dived off the Lizard peninsula this year I saw multiple octopuses,” the officer added. “They are sizeable. We have two species in these waters. One species is quite small, football-sized, but these common octopuses can be reaching impressive sizes.”

Looking Ahead & Coastal Highlights

A second gentle winter going into 2026 suggests the potential a repeat event next year, because based on records, under these conditions, the blooms have repeated for two consecutive years.

“However, it is unlikely, looking at history, that it will persist indefinitely,” they cautioned. “But the sea keeps giving us surprises at the moment so it’s a very uncertain scenario.”

The assessment also highlighted further encouraging coastal sightings along the coast, including:

• A record number of gray seals observed in Cumbria.
• Exceptional populations of puffins on Skomer.
• The first recording of an unusual mollusc in a northern county, typically a southwestern species.
• A type of blenny discovered off the coast of Sussex for the first time.

Not All Positive News

Challenges were also present, however. “The year was bookended by marine incidents,” said a head of marine conservation. “A major tanker collision in March and a spill of plastic pollution off the Sussex coast served as stark reminders. Conservation teams are making huge efforts to protect and restore our coasts.”