Unprecedented observations of one of the world's most intelligent invertebrates during the summer season have prompted the naming of 2025 as “the year of the octopus” in a seasonal assessment of Britain’s seas.
A mild winter and then a remarkably hot spring prompted a huge population of Mediterranean octopuses to take up residence along the shores from Cornwall to Devon, spanning the Cornish and Devonian coasts.
“The volume of octopuses caught was approximately thirteen times what we would usually anticipate in this region,” explained a marine life specialist. “Based on the totals, around 233 thousand octopuses were caught in British seas this year – which is a significant rise from the norm.”
The common octopus is indigenous to these waters but usually so scarce it is seldom observed. A population bloom is attributed to a combination of gentle winter conditions and a warm breeding season. Such favorable circumstances meant increased juvenile survival, potentially supported by significant populations of a favored prey species seen in the area.
The most recent occasion, an octopus bloom of this size was observed in the mid-20th century, with archival data indicating the last bloom prior to that was 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 living memory. Diver videos show octopuses being sociable – unlike their typical solitary behavior – and moving along the seabed on their arm ends. One individual was even seen investigating a diver's camera.
“The first time I dived there this year I saw five octopuses,” the specialist continued. “They are sizeable. There are two types in the region. The curled octopus is quite small, football-sized, but these common octopuses can be reaching impressive sizes.”
If conditions remain mild this coming winter could lead to another surge in 2026, because in the past, in similar situations, events have occurred consecutively for two years running.
“But, it's improbable, from previous blooms, that it will become a permanent fixture,” they cautioned. “But the sea keeps giving us surprises these days so it’s hard to forecast.”
The annual review also highlighted further encouraging coastal sightings along the coast, including:
The year had its low points, however. “The period was framed by environmental disasters,” said a head of marine conservation. “A significant shipping incident in March and the release of plastic pollution off the southern coast highlighted ongoing threats. Dedicated individuals are working tirelessly to safeguard and rehabilitate our coasts.”
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