The common octopus is found in temperate and tropical waters throughout the world, and is widespread across the Mediterranean and north through the coastal waters of Iberia and France.
However, much of the UK coast is beyond its normal range, the water being too cold for a cephalopod that may measure more than 1m in length and weigh up to 9kg.
Nevertheless, individuals are often found along Britain’s south and west coasts, and the smaller curled octopus (Eledone cirrhosa) – so named because of its tendency to rest with its arms tightly curled – is more widespread around UK shores.
Periodic ‘blooms’ see spikes in this mollusc’s population and distribution. Notable common octopus blooms were recorded in 1899, 1948 and 2022 – and 2025 was thought to have been a bumper year for the crustacean-loving cephalopod.
Being short-lived and fast-growing, the octopus is highly sensitive to changes in its environment. Shifts in water temperature, an increase in prey abundance or a decrease in predator numbers are all factors that may prompt fluctuations in population.
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Some of the octopus’s cousins are found in UK waters. We host two species of squid, the common (Loligo vulgaris) and long-finned (Loligo forbesii), and the common cuttlefish (Sepia officinalis), most often found off Britain’s southern and western coasts. Squid and cuttlefish also have beaks and eight arms, along with an additional pair of longer tentacles used for grabbing prey.
Unlike octopuses, the cuttlefish has an internal shell formed principally from aragonite, which aids buoyancy. These shells are often found washed up on beaches, and are sometimes given to caged birds or reptiles to provide supplementary calcium. Despite that buoyancy aid, cuttlefish tend to stay close to the sea floor in relatively shallow water.
Squid, however, are more powerful open-water swimmers. Each has an interior structure known as a pen or gladius, formed from chitin (the same material as the beaks), which is rather flexible, unlike the cuttlefish’s shell.
Can you fish octopus in the UK?
Octopus is not subject to quota in UK fisheries, and the opportunity to cash in on a bloom could help compensate those impacted by predation of crab and lobster. There are ethical and environmental issues to consider, though. Without regulation via quotas, octopus could be overfished.
Some people also object to eating such an intelligent animal – though the levels of emotional intelligence displayed by an octopus are little different from those of mammalian livestock that we commonly consume.
It’s certainly important to ensure sustainable harvesting of octopus, while allowing fishers an opportunity to exploit population blooms. Perhaps encouraging a British market that can adapt to changing availability of the species might result in measured responses to future shifts.
As sea temperatures continue to rise, the range and abundance of common octopus might expand. In the meantime, divers and snorkellers can enjoy more intimate underwater octopus encounters, observing and engaging with – perhaps even befriending – one of the ocean’s most extraordinary creatures.
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Top image: a curled octopus (Eledone cirrhosa) in Country Antrim, Northern Ireland. Credit: libbykeatley, CC BY 4.0, via Wikimedia Commons
