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

Unprecedented observations of one of the world's most intelligent invertebrates this past summer have led to the naming of 2025 as the octopus's year in a yearly report of Britain’s seas.

A Perfect Storm for a Population Boom

An unusually warm winter and then a very warm springtime triggered a huge population of *Octopus vulgaris* to take up residence along the southern coastline of England, spanning the Cornish and Devonian coasts.

“The volume of octopuses caught was roughly thirteen times what we would normally expect in the waters around Cornwall,” explained a marine life specialist. “When we added up the numbers, nearly a quarter of a million octopuses were found in these waters this year – which is a significant rise from historical averages.”

The Mediterranean octopus is native to British seas but typically so rare it is infrequently encountered. An explosive growth is attributed to a combination of gentle winter conditions and a warm breeding season. Such favorable circumstances meant increased juvenile survival, potentially supported by abundant stocks of spider crabs seen in the area.

An Uncommon Occurrence

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 last bloom prior to that was in the turn of the 20th century.

The remarkable abundance of octopuses meant they could be easily spotted in coastal areas for the first time in living memory. Video footage show octopuses gathering in groups – unlike their typical solitary behavior – and “walking” along the ocean floor on their arm ends. A curious octopus was even filmed grabbing submarine recording equipment.

“The first time I dived in that area this year I saw five octopuses,” they noted. “They are large specimens. There are two types in UK waters. The curled octopus is smaller, football-sized, but these common octopuses can be reaching impressive sizes.”

Predictions and Marine Joy

Another mild winter going into 2026 meant it was possible a repeat event the following year, because in the past, under these conditions, events have occurred consecutively for two years running.

“However, it is unlikely, based on past events, that it will persist indefinitely,” they stated. “Marine life is unpredictable currently so it’s a very uncertain scenario.”

The assessment also celebrated further encouraging coastal sightings around the UK coastline, including:

• Highest-ever counts of gray seals observed in Cumbria.
• Exceptional populations of puffins on Skomer.
• A first-ever sighting of a rare sea slug in Yorkshire, normally residing farther south.
• A Mediterranean fish species discovered off the coast of a southern county for the first occasion.

Not All Positive News

Not everything was good news, however. “The year was bookended by ecological challenges,” stated an expert. “A significant shipping incident in March and the release of industrial pellets off the Sussex coast served as stark reminders. Dedicated individuals are making huge efforts to protect and restore our marine habitats.”