PML PROJECT WILL HELP PREDICT FUTURE OCTOPUS BLOOMS

PML project will help predict future octopus blooms. A diverse range of Plymouth Marine Laboratory (PML) researchers have come together to develop a methodology that would help stakeholders – from fishers and citizens, to scientists and decisionmakers – in the Southwest anticipate future octopus blooms, adapt to changing conditions, and support more resilient, data-driven decision-making.

The team, bringing skills from a range of disciplines – including Earth observation, data modelling, research software engineering and digital infrastructure – secured funding for the novel research last year when they were selected as one of the three winning teams in the 2025 Blue-Cloud Hackathon.

In the Hackathon, through their project titled ‘Octopulse’, the team analysed both historical and real-time data from the Western Channel Observatory – an oceanographic time-series and marine biodiversity reference site in the Western English Channel, and one of the most widely studied bodies of water in the world – alongside satellite and model data, to help communities to identify the ‘perfect’ conditions that drive octopus blooms.

Following their success in the Hackathon, the team is now using the funding to develop the concept further.

Background: the octopus bloom in the Southwest 

The Common octopus (Octopus vulgaris) is native to UK waters but is typically rare, favouring warmer seas further south in Europe and the Mediterranean.

The current bloom in the Southwest UK, which really accelerated from January 2025 – and is still continuing over one year on – is having significant effects on both fisheries and marine ecosystems.

Beshlie Pool, Executive Officer of the South Devon and Channel Shellfishermen Ltd, explains the situation as it stands, and the impacts on local livelihoods:

“2025 brought huge changes to traditional fisheries across the Southwest. In our area, Common octopus began appearing in huge numbers from late February, leaving a trail of destruction behind, with crab and lobster pots filled with the remains of eaten shellfish.”

Beshlie continues:

“As a community of crab fishermen, for whom crab and lobster is our heritage and regional identity, the influx of Common octopus has been incredibly concerning.”

“Whilst there are some who have been able to catch octopus – because of where they fish – others have not, and instead have only seen the remains of what has been eaten. It is a very difficult time for our community.”

“We value all work that can help us learn to predict what may come next.”

Crab and lobster populations are not the only species affected, as Jack West of Ann Louise Fishing in Mevagissey, Cornwall explains:

“I’m a scallop fisherman, and since the octopus bloom we’ve seen a major impact on the scallop population – scallops are now almost non-existent in some bays. While it’s created an opportunity for some of us to target octopus, and in the short term that’s been financially beneficial as they return good prices, the longer-term picture is a real concern. Fishing has already been very poor over the past couple of years, and there are worries about what this means for future stocks and breeding populations.”

“Although I’ve personally been able to build a market for octopus and adapt – building a good client base with pubs and restaurants to buy octopus catches – the situation is so severe for scallops that, this year, I won’t be fishing for scallops at all.”

“Now in March, we’re already fishing for octopus again this year. It’s still early in the season, but we’re getting catches and expect to see much more as the weather warms.”

“Others in the industry – particularly those in crab and lobster fisheries – have been hit even harder and some have not been able to adapt like we have. The longer-term impacts on shellfish stocks and the wider fishing industry remain a serious concern.”

In January this year, a report involving scientists from Plymouth Marine Laboratory revealed the scale, causes and consequences of the bloom.

The report, funded by Defra, Plymouth City Council and Devon County Council, and led by the Marine Biological Association (MBA) in collaboration with Plymouth Marine Laboratory (PML), the University of Plymouth and an independent consultant, drew on data from scientists, fishermen and citizen scientists.

Access the full report: ‘Common octopus (Octopus vulgaris) blooms off the Southwest of the UK: History, trends, causes and consequences’

The report found a climate-driven pattern – all major octopus blooms, including this one, have coincided with unusually warm conditions, which are becoming more frequent with climate change.

Sustained easterly winds may have also helped transport young octopus larvae from the Channel Islands and northern France. Ocean current modelling supports this, showing that larvae from Guernsey, which has seen its own octopus bloom since 2024, likely contributed to the UK surge.

Image: Two Common octopus and the remains of a lobster hauled in from a lobster pot. Image credit: South Devon and Channel Shellfishermen Ltd. 

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