Porth Kerris Divers hosted a visit from biologist Lizzie Daly which was broadcast on the BBC's One Show last night featuring the now common appearance of Mediterranean octopus in Cornish waters.
In response to the bloom, Devon & Severn Inshore Fisheries and Conservation Authority (D&SIFCA) is working with local fishermen to assess the impact these creatures with an appetite for lobsters and other shellfish are having on the sea bed environment.
An octopus "bloom" is occurring in the English Channel, as a new generation of common octopuses are developing in seabed dens, with their mothers tending to the eggs. Once hatched, the larval octopuses will disperse. The abundance of these cephalopods is a blessing for some fishermen but a problem for others.
Since 2022, fishers in both northern France and South West England have been catching an increasing number of common octopus (Octopus vulgaris). In May 2025, a single trawler operating out of Newlyn, Cornwall, landed a record-breaking 20 tonnes of octopus, valued at £158,000. For some, this surge in abundance is a blessing. The common octopus is a high-value, non-quota species, meaning there's no limit on what can be caught, which can be a boon for the small-scale fishing sector.
However, for many, this influx is a major problem. These intelligent and adaptable predators are entering crab and lobster pots, where they feast on the shellfish inside. This phenomenon, which has occurred before in 1900 and 1950, has left many shellfishermen with no choice but to stop fishing. The influx is of great concern to the South Devon and Channel Shellfishermen fleet. While some fishers are able to make a living by catching octopus, others are seeing a significant drop in their traditional catches.
Alix Harvey, an Ecology Laboratory and Research Aquarium Manager at the Marine Biological Association (MBA), notes that cephalopods like squid, cuttlefish, and octopus are generally "winners" when it comes to changing seas 🦑. Their short lifespan, rapid reproduction, and intelligence enable them to quickly take advantage of new environments.
A Changing Environment
Decades ago, surveys from the 1950s octopus boom showed that octopus larvae originated on the south side of the English Channel. This year, however, octopus have been seen breeding on the English side. After the larvae settle out of the plankton, they need a mild winter to survive, a condition that is becoming more common around southern England as sea temperatures rise.
Fishers and Regulators Adapt Together
In response to the influx, the Devon & Severn Inshore Fisheries and Conservation Authority (D&SIFCA) is working with local fishers. They've clarified existing regulations, specifically the Potting Permit Byelaw, which requires "escape gaps" on crab and lobster pots. These gaps, originally meant to allow juvenile crustaceans to escape, are also a convenient exit for the voracious octopuses after they've eaten the catch.
D&SIFCA has clarified that if fishers are targeting octopus only, they can close the escape gap. However, any crustaceans caught must be returned to the sea. Conversely, if fishing for crab, lobster, or spiny lobster, the escape gap must remain open. This collaborative approach between D&SIFCA and fishers is crucial for gathering evidence on how effective closing the escape gap is for catching octopus.
A recent national meeting brought together fishers, the Marine Management Organisation, and scientists to discuss the situation. The conversation focused on the impacts of the octopus influx, how to protect existing shellfish stocks, and potential management solutions for both the short and long term.
An alignment of environmental factors has once again allowed the common octopus to expand its range into the northern parts of the English Channel. Understanding how long-term climate and ecological trends will affect the future distribution of O. vulgaris is important, as the octopus's fate is tied to the livelihoods of fishers in the region. Interdisciplinary research will be essential for developing policies that support the environment, fishers' livelihoods, and the resilience of coastal communities.
Further Reading
Garstang, W. 1900. The plague of octopus on the south coast, and its effect on the crab and lobster fisheries. Journal of the Marine Biological Association of the United Kingdom 6: 260-273. doi:10.1017/S0025315400006639
Rees, W.J. and Lumby, J.R. 1954. The abundance of octopus in the English Channel. Journal of The Marine Biological Association of the United Kingdom 33: 515-536.
Schickele, A., Francour, P. and Raybaud, V. 2021. European cephalopods distribution under climate-change scenarios. Scientific Reports 11: 3930 (2021). doi.org/10.1038/s41598-021-83457-w
Full story courtesy of www.devonandsevernifca.gov.uk/octopus-escape-gaps
Since 2022, fishers in both northern France and South West England have been catching an increasing number of common octopus (Octopus vulgaris). In May 2025, a single trawler operating out of Newlyn, Cornwall, landed a record-breaking 20 tonnes of octopus, valued at £158,000. For some, this surge in abundance is a blessing. The common octopus is a high-value, non-quota species, meaning there's no limit on what can be caught, which can be a boon for the small-scale fishing sector.
However, for many, this influx is a major problem. These intelligent and adaptable predators are entering crab and lobster pots, where they feast on the shellfish inside. This phenomenon, which has occurred before in 1900 and 1950, has left many shellfishermen with no choice but to stop fishing. The influx is of great concern to the South Devon and Channel Shellfishermen fleet. While some fishers are able to make a living by catching octopus, others are seeing a significant drop in their traditional catches.
Alix Harvey, an Ecology Laboratory and Research Aquarium Manager at the Marine Biological Association (MBA), notes that cephalopods like squid, cuttlefish, and octopus are generally "winners" when it comes to changing seas 🦑. Their short lifespan, rapid reproduction, and intelligence enable them to quickly take advantage of new environments.
A Changing Environment
Decades ago, surveys from the 1950s octopus boom showed that octopus larvae originated on the south side of the English Channel. This year, however, octopus have been seen breeding on the English side. After the larvae settle out of the plankton, they need a mild winter to survive, a condition that is becoming more common around southern England as sea temperatures rise.
Fishers and Regulators Adapt Together
In response to the influx, the Devon & Severn Inshore Fisheries and Conservation Authority (D&SIFCA) is working with local fishers. They've clarified existing regulations, specifically the Potting Permit Byelaw, which requires "escape gaps" on crab and lobster pots. These gaps, originally meant to allow juvenile crustaceans to escape, are also a convenient exit for the voracious octopuses after they've eaten the catch.
D&SIFCA has clarified that if fishers are targeting octopus only, they can close the escape gap. However, any crustaceans caught must be returned to the sea. Conversely, if fishing for crab, lobster, or spiny lobster, the escape gap must remain open. This collaborative approach between D&SIFCA and fishers is crucial for gathering evidence on how effective closing the escape gap is for catching octopus.
A recent national meeting brought together fishers, the Marine Management Organisation, and scientists to discuss the situation. The conversation focused on the impacts of the octopus influx, how to protect existing shellfish stocks, and potential management solutions for both the short and long term.
An alignment of environmental factors has once again allowed the common octopus to expand its range into the northern parts of the English Channel. Understanding how long-term climate and ecological trends will affect the future distribution of O. vulgaris is important, as the octopus's fate is tied to the livelihoods of fishers in the region. Interdisciplinary research will be essential for developing policies that support the environment, fishers' livelihoods, and the resilience of coastal communities.
Further Reading
Garstang, W. 1900. The plague of octopus on the south coast, and its effect on the crab and lobster fisheries. Journal of the Marine Biological Association of the United Kingdom 6: 260-273. doi:10.1017/S0025315400006639
Rees, W.J. and Lumby, J.R. 1954. The abundance of octopus in the English Channel. Journal of The Marine Biological Association of the United Kingdom 33: 515-536.
Schickele, A., Francour, P. and Raybaud, V. 2021. European cephalopods distribution under climate-change scenarios. Scientific Reports 11: 3930 (2021). doi.org/10.1038/s41598-021-83457-w
Full story courtesy of www.devonandsevernifca.gov.uk/octopus-escape-gaps
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