Defra report into deaths of hundreds of crabs on North East beaches gives its findings
Sightings across the North East of hundreds of dead crabs, lobsters and other crustaceans washed up on our region’s beaches are believed to have been caused by an algal bloom.
The verdict has been published as part of a “significant” investigation carried out by the Department for Environment, Food & Rural Affairs (Defra).
In October, Hartlepool residents reported seeing a large number of dead crabs washed up on the beach at Seaton Carew with Carl Clyne saying he spotted “well over a hundred” dead crabs while walking his dog.
With the investigation complete, the report stated: “From the evidence found during the investigation it’s unlikely that chemical pollution, sewage or infectious aquatic animal diseases were the cause of the deaths. No traces of chemical contaminants have been found that could have caused an event of this scale.
"Follow up survey work carried out by the Environment Agency on the 18th and 19th of January 2022 has also shown live healthy crabs present in the area, albeit in reduced numbers.”
The investigation also examined the potential impact of dredged sediment which may have contained chemical pollutants. The investigation found chemical deposits didn’t exceed “action levels” that would be harmful to marine life.
The report stated: “A further review of dredging, disposal activity and water samples found no evidence of a link between the disposal of dredged sediment and the mass crustacean deaths.”
Initially the deaths were believed to have possibly been caused by the presence of the chemical pyridine which was detected in some of the crabs from impacted areas.
However the report concluded: “Investigations established that pyridine was not present in water and surface sediment samples collected off the Tees, and that pyridine is found in crabs taken from non-impacted areas. As such, the presence of pyridine in crab is likely to be linked to biological processes.”
The investigation results from cyanide analysis were also shown be “below the detection limit of the test”.
As such the report concluded: “Following significant testing and modelling to rule out possible causes, Defra and partner agencies consider the deaths of the crabs and lobsters potentially resulted from a naturally occurring harmful algal bloom.”