2025 Proclaimed the 'Year of the Octopus' Along Britain's South Coast.

Exceptionally high sightings of one of the world's most intelligent invertebrates over the summer months have resulted in the designation of 2025 as “the year of the octopus” in an annual review of UK coastal waters.

Ideal Conditions Leading to an Explosion

A gentle winter followed by a remarkably hot spring prompted unprecedented numbers of common octopuses (*Octopus vulgaris*) to settle along the southern coastline of England, from Penzance in Cornwall to south Devon.

“The reported landings was of the order of about 13 times what we would typically see in Cornish waters,” commented a marine life specialist. “When we added up the numbers, approximately 233,000 octopuses were found in UK waters this year – which is a significant rise from what is typical.”

The Mediterranean octopus is native to these waters but ordinarily in such small numbers it is infrequently encountered. A population bloom is the result of a combination of a mild winter and favorable spring temperatures. These ideal conditions meant more larvae, potentially supported by abundant stocks of spider crabs seen in the area.

A Historic Event

Previously, a population surge of this scale comparable was documented in 1950, with archival data indicating the previous major event occurred in 1900.

The huge numbers of octopuses meant they could be readily observed in nearshore environments for the first time in living memory. Diver videos show octopuses gathering in groups – unlike their typical solitary behavior – and “walking” along the seabed on their tentacle tips. A curious octopus was even recorded reaching for a diver's camera.

“The first time I dived in that area this year I saw five of these creatures,” the officer added. “They are sizeable. We have two species in the region. The curled octopus is quite small, the size of a ball, but the *Octopus vulgaris* can be reaching impressive sizes.”

Predictions and Marine Joy

If conditions remain mild going into 2026 meant it was possible a repeat event in 2026, because based on records, with such patterns, populations have surged again for two years in a row.

“Still, the chances are low, from previous blooms, that it will become a permanent fixture,” they said. “But the sea keeps giving us surprises at the moment so it’s quite an unpredictable situation.”

The report also celebrated other “surprises, successes and joyful moments” across British shores, including:

• A record number of grey seals observed in one northern region.
• Exceptional populations of the iconic seabirds on an island off Wales.
• The initial discovery of a rare sea slug in Yorkshire, usually found in the south-west.
• A variable blenny discovered off the coast of a southern county for the inaugural time.

A Note of Caution

The year had its low points, however. “The period was framed by marine incidents,” said a head of marine conservation. “A significant shipping incident in the North Sea and an accidental discharge of plastic pollution off the Sussex coast served as stark reminders. Conservation teams are working tirelessly to protect and restore our marine habitats.”