2025 Proclaimed 'The Octopus Year' Along England's South Coast.

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

A Confluence of Factors Leading to an Explosion

An unusually warm winter and then a remarkably hot spring prompted unprecedented numbers of common octopuses (*Octopus vulgaris*) to settle along the southern coastline of England, across the southwestern peninsula.

“The scale of the catch was of the order of about 13 times what we would usually anticipate in the waters around Cornwall,” explained an ocean conservation expert. “Calculating the figures, nearly a quarter of a million octopuses were present in UK waters this year – which is a significant rise from historical averages.”

The common octopus is native to UK waters but usually so scarce it is infrequently encountered. A sudden increase is caused by the dual effect of gentle winter conditions and a warm breeding season. This perfect scenario meant increased juvenile survival, maybe aided by abundant stocks of spider crabs seen in the area.

A Historic Event

Previously, an octopus bloom of this size was documented in the mid-20th century, with historical records indicating the previous major event occurred in the turn of the 20th century.

The huge numbers of octopuses meant they could be frequently seen in coastal areas for the first time in recent history. Video footage show octopuses gathering in groups – unlike their typical solitary behavior – and ambulating along the ocean floor on their arm ends. A curious octopus was even seen investigating submarine recording equipment.

“The first time I dived off the Lizard peninsula this year I saw multiple octopuses,” they noted. “They are sizeable. Two kinds exist 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

A second gentle winter going into 2026 could lead to another surge the following year, because historically, with such patterns, events have occurred consecutively for two consecutive years.

“However, it is unlikely, from previous blooms, that it will go on for a long time,” they cautioned. “But the sea keeps giving us surprises these days so it’s hard to forecast.”

The assessment also celebrated additional positive marine news along the coast, including:

• Unprecedented numbers of grey seals seen in Cumbria.
• Record numbers of puffins on an island off Wales.
• The first recording of an unusual mollusc in Yorkshire, typically a southwestern species.
• A variable blenny spotted off the coast of Sussex for the first occasion.

Not All Positive News

Not everything was good news, however. “The calendar year was marked by ecological challenges,” said a head of marine conservation. “A significant shipping incident in March and the release of tonnes of plastic biobeads off the Sussex coast were serious issues. Dedicated individuals are putting in immense work to defend and heal our coasts.”