The crustaceans were found dead or dying along more than 70 kilometers (44 miles) of coastline in late 2021, with some displaying unusual “twitching” while in the throes of death.
Environmentalists suspected toxins released by dredging to expand a port in Teesside, a heavily industrial area, might have been responsible. Research last year by academics, backed by the fishing industry, suggested the industrial pollutant pyridine, possibly from dredging at the mouth of the River Tees, as a potential cause.