New summer surveys to try to identify cause of crayfish deaths - Environment Agency

The Environment Agency is carrying out a series of summer surveys to try to identify the cause of unusual symptoms in an endangered native species.

Last autumn around 100 native white clawed crayfish were found dead in the River Wansbeck catchment in Northumberland.

The subsequent investigation determined crayfish displaying similar symptoms - unusual orange patches on their shell – were widespread across the Wansbeck catchment as well as areas of the neighbouring rivers Tyne and Blyth catchments.

Now the Environment Agency is carrying out surveys across Northumberland and the North East through the summer to determine current populations of the native species.

The surveys will also be identifying locations where crayfish are displaying the unusual symptoms.

Intensive surveys on the Hart Burn, where the initial deaths were reported, as well as at some other sites, will help the Environment Agency understand the mortality rates in the population.

Working closely with experts

The team is working with both the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and experts at Teesside University in efforts to understand more about the situation.

Sarah Jennings, Area Environment Manager at the Environment Agency said: “After a pause during winter and spring while the river levels were high we are now back out at rivers right across the North East to carry out widespread crayfish surveys. We are working closely with experts at Cefas and Teesside University on sampling and analysis in efforts to understand more about what is happening to this important species. There’s a lot we still don’t know but we hope this new work sheds some light as we continue efforts to safeguard the future of the white clawed crayfish.”

Early surveys indicate that healthy populations of the native white clawed crayfish still remain in the North East – including in the Wansbeck catchment - but symptoms persist in some areas.

Surveys also show populations of the invasive American signal crayfish are also affected by the same symptoms.