2025 Proclaimed The Year for Octopuses Off Britain's South Coast.

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

Ideal Conditions Leading to an Explosion

A gentle winter followed by a very warm springtime triggered a massive influx of Mediterranean octopuses to take up residence along the southern coastline of England, from Penzance in Cornwall to south Devon.

“The volume of octopuses caught was of the order of about thirteen times what we would usually anticipate in Cornish waters,” stated a marine life specialist. “Calculating the figures, around 233 thousand octopuses were found in British seas this year – representing a massive jump from the norm.”

*Octopus vulgaris* is native to British seas but typically so rare it is infrequently encountered. A population bloom is the result of a combination of gentle winter conditions and a warm breeding season. These ideal conditions meant a higher survival rate for young, potentially supported by large numbers of spider crabs also recorded.

A Historic Event

The most recent occasion, a population surge of this scale of this size was documented in the mid-20th century, with archival data indicating the previous major event happened in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be frequently seen in nearshore environments for a rare occurrence. Underwater recordings show octopuses congregating together – they are usually solitary – and moving along the bottom on the tips of their limbs. A curious octopus was even filmed grabbing a diver's camera.

“During a first dive in that area this year I saw multiple octopuses,” the specialist continued. “They are sizeable. There are two types in these waters. One species is quite small, about the size of a football, but these newcomers can be up to a metre and a half wide.”

Future Prospects and Other Surprises

A second gentle winter going into 2026 suggests the potential another surge the following year, because based on records, under these conditions, events have occurred consecutively for two consecutive years.

“Still, the chances are low, based on past events, that it will go on for a long time,” they said. “Marine life is unpredictable these days so it’s quite an unpredictable situation.”

The assessment also highlighted other “surprises, successes and joyful moments” along the coast, including:

• Highest-ever counts of grey seals observed in Cumbria.
• Peak 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 discovered off the coast of Sussex for the first occasion.

Not All Positive News

The year had its low points, however. “The period was framed by environmental disasters,” noted a conservation leader. “A significant shipping incident in the North Sea and the release of tonnes of plastic biobeads off the southern coast were serious issues. Staff and volunteers are putting in immense work to safeguard and rehabilitate our shorelines.”