2025 Declared the 'Year of the Octopus' Off Britain's South Coast.

Exceptionally high encounters of one of the world's most intelligent invertebrates this past summer have prompted the declaration of 2025 as “the year of the octopus” in a yearly report of Britain’s seas.

Ideal Conditions Leading to an Explosion

An unusually warm winter followed by an exceptionally warm spring triggered a massive influx of common octopuses (*Octopus vulgaris*) to establish themselves along England’s south coast, across the southwestern peninsula.

“The scale of the catch was roughly over a dozen times what we would typically see in Cornish waters,” commented a marine life specialist. “When we added up the numbers, around 233 thousand octopuses were present in UK waters this year – which is a significant rise from what is typical.”

The common octopus is indigenous to these waters but ordinarily in such small numbers it is rarely seen. A sudden increase is the result of a combination of a mild winter and favorable spring temperatures. This perfect scenario meant increased juvenile survival, potentially supported by significant populations of a favored prey species noted in recent years.

An Uncommon Occurrence

The last time, a population surge of this scale of this size was observed in the mid-20th century, with historical records indicating the one before that was in the turn of the 20th century.

The sheer quantity of octopuses meant they could be easily spotted in shallow waters for the first time in living memory. Video footage show octopuses gathering in groups – they are usually solitary – and ambulating along the ocean floor on their arm ends. One individual was even filmed grabbing a diver's camera.

“During a first dive there this year I saw multiple octopuses,” they noted. “They are sizeable. There are two types in UK waters. One species is smaller, about the size of a football, but these common octopuses can be with a span of 1.5 meters.”

Predictions and Marine Joy

Another mild winter going into 2026 meant it was possible a repeat event next year, because based on records, under these conditions, the blooms have repeated for two years in a row.

“But, it's improbable, looking at history, that it will go on for a long time,” they cautioned. “Marine life is unpredictable currently so it’s quite an unpredictable situation.”

The report also highlighted additional positive marine news along the coast, including:

• A record number of gray seals recorded in Cumbria.
• Record numbers of the iconic seabirds on an island off Wales.
• The initial discovery of an unusual mollusc in Yorkshire, usually found in the south-west.
• A type of blenny found off the coast of a southern county for the first time.

Environmental Concerns

The year had its low points, however. “The calendar year was marked by marine incidents,” said a head of marine conservation. “A significant shipping incident in the North Sea and a spill of plastic pollution off the Sussex coast served as stark reminders. Conservation teams are putting in immense work to safeguard and rehabilitate our shorelines.”