New research by university scientists has discovered the reason for the mass sea life die-off in the North East over the past year. The culprit they found is probably toxic pollution dredged from the River Tees, and the finding destroys the explanation given by the government’s Department for Environment, Food and Rural Affairs (Defra).
In October last year and earlier this year, beaches in the North East and North Yorkshire were covered in thousands of dead and dying marine life. They were mostly creatures that feed on the seabed, plus their predators like seals and porpoises. Crabs were the most affected. Local fishermen found entire stretches of lifeless sea that have yet to recover.
Defra closed the case, dismissing the die-off as a natural event, the outcome of an algal bloom. Their explanation overlooked the fact that levels in the dead crabs of the industrial chemical pyridine were up to 74 times higher than in crabs in Cornwall.
The Defra response was greeted with scepticism locally, suspicion falling on pollution in the Tees, the most toxic waterway in Britain, dumped in the open sea by dredgers.
A report by independent marine expert Tim Deere-Jones rejected the algal bloom theory, pointing the finger at pyridine. The chemical could be a legacy of old industry or a recent contaminant from modern production.
The Deere-Jones study was commissioned by Whitby fishermen. The new university research was contracted by the North East Fishing Collective, a group of fishermen and anglers associations and financed by crowdfunding.
The new report’s findings have garnered widespread attention from the mainstream media including Channel 4 News and ITV.
But what exactly is in the report?
This eagerly-awaited study is at present an “interim draft report” that can’t be shared online. It is hoped the academic version of the article will be peer-reviewed in the near future. The 41-page investigation was led by Joe Redfern, a marine biologist and lobster hatchery owner and involved scientists at York, Newcastle, Hull and Durham universities.
The executive summary was produced by the University of Durham.
The study questioned Defra’s claim that a natural algal bloom was to blame. Although a bloom was present at the time of the die-off it was not unusually large. Nor was the species that Defra identified the toxic variety normally associated with die-offs. Toxic algal blooms will kill off everything, but the die-off killed mostly crabs and lobsters.
Scientists at Newcastle University experimented on live healthy crabs from Northumberland. Exposing the crabs to pyridine, they found that 0.49mg of the chemical per litre of seawater was enough to kill half the study’s crabs within 72 hours. That’s equivalent to a single droplet of pyridine in a litre of seawater.
At over 20mg of pyridine per litre of seawater, the crabs rapidly twitched their walking legs.
At 100mg per litre, the crabs went into convulsions, sometimes somersaulting followed by paralysis. They often landed on their backs. All the crabs tested at this level of concentration died within six hours.
The study concludes that pyridine can induce the same twitching behaviour in crabs that was seen during the die-off. The toxin poisons crabs at lower concentrations than it affects fish.
Newcastle’s computer simulation of pyridine release during dredging demonstrated that the chemical could reach Whitby. The simulation of coastal waters showed the spread of pyridine near Teesmouth in September and October 2021, during a dredging campaign and just before the first wave of the die-off.
The simulation showed that plumes of any toxin could rise from the sea bed after storms or dredging.
The Defra-led Joint Agency Report produced after the die-off didn’t find pyridine in the water, but they didn’t test the sediment.
The University of Hull analysed the satellite data for an algal bloom and found that a bloom did occur at the time of the die-off but the species could not be identified.
The new report concluded:
“1) Our preliminary evidence suggests that crab deaths are more consistent with poisoning by industrial toxins than by natural algal toxins.
“2) Many uncertainties remain: targeted sediment and water sampling needs to happen around Teesside as a matter of urgency if we are to understand how to prevent further economically and socially damaging mass mortality.”
Will the government listen?
Whether the new Truss government – which has just demolished environmental legislation – will listen is doubtful.
Then there’s the hostility of Tory Tees Valley Metro Mayor Ben Houchen to any environmental concerns. They might delay his pet project, the massive Teesside Freeport development which involves even deeper dredging. Although the pollution is undermining the local tourism and fishing industries, Houchen’s eyes are on the bigger Freeport fish.