Defra and partner agencies have completed a thorough investigation of the cause of dead crabs and lobsters which were found washed up on the North East coast between October and December 2021.

Following significant testing and modelling to rule out possible causes, Defra and partner agencies consider that the deaths of the crabs and lobsters potentially resulted from a naturally occurring harmful algal bloom.

From the evidence found during the investigation it is 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.

A review of dredging activity and water samples found no evidence of a link between the disposal of dredged sediment and the deaths. The sampling of sediment that has been licenced by the MMO for disposal to the designated sites off the Tees confirmed that no chemical determinants exceeded concentrations (‘Action Levels’) that would be harmful to marine life. 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.

This investigation was a multi-agency response, involving Defra, the Environment Agency, Centre for Environment, Fisheries and Aquaculture Science (Cefas), North Eastern Inshore Fisheries and Conservation Authority (NEIFCA), the Marine Management Organisation (MMO), Food Standards Agency (FSA), UK Health Security Agency (UKHSA), to identify what could have caused the event.

Evidence gathered by Government scientists and multiple agencies throughout this investigation will continue to be collated and studied. While this is no longer an active investigation, the agencies will continue to work with local fishers and remain on standby to respond if further events occur.

More on this story can be found here.