Report published into shellfish deaths on Teesside coast
An independent investigation into the deaths of thousands of shellfish off the Teesside and North Yorkshire coast suggest it may have been down to disease or parasites.
Last updated 20th Jan 2023
UPDATE: The MPs for Middlesbrough and Stockton North have both issued statements.
Andy McDonald, MP for Middlesbrough, said:
“It's extremely disappointing that this report does not provide any definitive answers as to why this ecological disaster happened and deaths continue. It effectively says, ‘we don’t know why it happened’.
"It resolves nothing. It does say that the previously offered government explanation of algal bloom was wrong as many had said it was, but equally discounts the chemical pyridine on the basis that the spread of the disaster is too big for it to have been from such a cause.
"It cannot be left that the cause is simply written off as being unidentified. There has to be a causal factor, or factors, for such a devastating event, but quite simply that cause or causes can't currently be defined. That being so, further investigation is needed. When Covid first appeared, scientists were wonderfully accurate in identifying the strain and vaccination to address it.
"With an ecological disaster such as we have seen here in our region, it is imperative that the experts and scientists continue to investigate so as to take any necessary steps to address the cause and so that our fishers can have some semblance of understanding as to if and when the stocks might return.”
Meanwhile, Stockton North's Alex Cunningham said;
“Today the government have been found out – but it is the people of Teesside who have paid the price. For over fifteen months I and others across Teesside, North Yorkshire and County Durham have been calling for answers on the mass crustacean die-offs that have blighted our environment and have had a detrimental impact on our local fishing industry. I’m pleased that this scientific assessment has shed some light on the matter, and I want to the thank Sir Patrick Vallance and his team for the work they have done on it.
“We now know that the algal bloom theory which the Prime Minister, Ministers, Tory MPs and the Tees Valley Mayor have hidden behind for so long is an unlikely cause for the mass deaths. For months they told us that an algal bloom is the cause and have rubbished anyone who has dared to challenge this theory.
“Just think of the time they could have saved – and anxieties they could have allayed – had they held up their hands, accepted that it was an inconclusive theory, and agreed to carrying out more testing and investigations from the outset. Sadly local Tories seem to think the matter is now closed with this report and are more concerned with protecting the Tees Valley Mayor’s flagship policy.
“As far as I and many others are concerned the matter is very much not closed. This investigation is a good first step to getting to the bottom of this issue. We now need a fully independent and entirely transparent investigation in to the matter with access to all areas for sampling and testing. Only then will get to the bottom of this environmental tragedy of epic proportions.”
And a statement from the Tees Valley Mayor reads:
Tees Valley Mayor Ben Houchen said: “Having read the report produced by Sir Patrick Vallance’s independent panel of marine experts it is clear that neither dredging, nor any work carried out by the Freeport, played a role in the crustacean deaths that occurred in October 2021.
“As mayor I will always take decisions based on the science and evidence provided by experts. Today’s report is thorough, conclusive and - as anyone would expect - we will follow the science.
"When I was elected, I promised former steelworkers who worked on that site that I would create a new thriving industry of the future with thousands of good-quality local jobs for local people. Today, backed by the science, we can look every single one of them in the eye and say the work we are doing, in an area that means so much to so many people, is safe and is of the highest possible standard.
“The wash-up in 2021 was devastating for our fishing community - one of our proudest industries with some of the most hard-working people on Teesside. Their industry has been ruined by a natural disaster and it is now essential Government steps up and supports them to recover from the events of October 2021. I've said this from day one and will continue to press the case with ministers.
“I always have, and I always will, work tirelessly to deliver jobs and investments for Teesside, Darlington and Hartlepool. That work will only intensify in the coming weeks to continue to deliver for the people I represent.”
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An independent investigation into the deaths of thousands of shellfish off the Teesside and North Yorkshire coast suggest it may have been down to disease or parasites.
It follows a row between people working in the fishing industry and the Government over the cause.
When the government carried out the initial investigation into the deaths of the crabs and lobsters- it blamed it on "harmful algae".
But people working in the fishing industry - who say it's significantly damaged their trade- rejected those findings- instead putting the deaths down to dredging in the River Tees.
Ministers agreed to carry out a fresh investigation- and an independent panel's now returned those results.
It says although there's no direct evidence of a disease or parasite, it would explain the key observations.
The panel, made up of experts from academia and industry, was chaired by Defra’s Chief Scientific Adviser Gideon Henderson with input from the Government Chief Scientific Adviser, Sir Patrick Vallance.
They investigated a number of possible causes for the unusual crab deaths which started in October 2021 including a potential disease or parasite, a harmful algal bloom, chemical toxicity including pyridine, and dredging which could have released a toxic chemical. Each of these potential causes was assessed according to the likelihood of the occurrence.
The key observations that must be explained by any cause include: Mortality over a sustained period and along at least 70km of coastline; the unusual twitching by dying crabs observed in many locations; and the deaths being dominantly crustaceans rather than a wider range of species.
The panel concluded:
It is about as likely as not that a pathogen new to UK waters – a potential disease or parasite - caused the unusual crab mortality. There are pathogens known to cause similar symptoms to those observed in the north-east and these pathogens have caused mortality events and declines in crustacean populations around the world. No significant pathogens were identified in the north-east crabs but full molecular screening was not conducted at the time of the initial investigation.
It is unlikely that a harmful algal bloom or that a loss of oxygen in the water associated with the algal bloom caused the crab deaths. The panel assessed satellite data and water-column measurements and concluded that the presence of an algal bloom in the area during September 2021 was likely but it was unlikely that the bloom persisted beyond October 2021.
It is very unlikely that pyridine or another toxic pollutant caused the crab deaths. The panel considered industries on Teesside and concluded they could not be sources of any significant volume of pyridine during the period of the crab deaths. Measurements of seawater by the Environment Agency and York University could not detect pyridine. Sediment measures of pyridine from dredged material and other toxic chemicals found in sediments in the Tees are significantly lower than the levels which would cause crab mortality.
It is very unlikely that maintenance dredging, as required to keep the port open, was the cause; a dredger operated in the channel offshore Teesside during late September and early October 2021 but the maximum possible release of toxic chemicals, including of pyridine, caused by this activity is significantly too small to cause crab mortality.
Capital dredging (i.e. as required to expand the port) was last carried out in December 2020, some time before deaths started in October 2021. Further capital dredging did not commence until September 2022. It is therefore exceptionally unlikely that capital dredging on the Tees caused the crab mortality seen in the region.
Although there is no direct evidence of a novel pathogen - a disease or parasite - it would explain the key observations including mortality over a sustained period and along 70km of coastline, the unusual twitching of dying crabs and the deaths being predominantly crabs rather than other species.
It is also possible that a combination of factors lead to the unusual mortality, rather than one of the factors the panel considered.
Sir Patrick Vallance, Government Chief Scientific Adviser, said:
"I would like to thank the scientists who have been involved in the expert assessment of this unusual crustacean mortality. For a complex issue like this it is important to have a range of experts involved who can offer independent challenge and analysis.
"Whilst with the current data there cannot be a definitive answer, the options for possible causes and an analyses of likelihood are clearly laid out in the report."
Gideon Henderson, Defra Chief Scientific Adviser, said:
"The report summarises thorough and insightful analysis of diverse relevant data by an impressive group of leading marine scientists from across the UK. Their combined knowledge allowed expert assessment of all possible causes of the unusual crustacean mortality.
"The panel was unable to identify a single clear cause, but it has been able to point to those more likely to explain the key features of the outbreak.
Environment Secretary Thérèse Coffey asked Defra’s Chief Scientific Advisor Gideon Henderson to liaise with the Government Chief Scientific Adviser Sir Patrick Vallance to establish an independent group, following a request from the Environment, Farming & Rural Affairs (EFRA) Select Committee. The Crustacean Mortality Expert Panel (CMEP) was convened from December 2022 to independently assess the causes of the unusual deaths.