Race on to save endangered crayfish as experts remain stumped by mystery deaths in River Wansbeck

Tom Barton has this report

A rescue mission is underway to try and protect an internationally important population of crayfish in Northumberland.

The River Wansbeck is one of the last remaining strongholds for the endangered native white-clawed crayfish but in the last few weeks around 100 have been found dead in the area after developing unexplained symptoms.

The die-off has left experts stumped despite weeks of investigation.

Sarah Jennings, area manager for the Environment Agency, said: “We've been able to rule out some really serious diseases like crayfish, plague, white spot, brown spot diseases. But we do remain really quite concerned.

"We don't quite have all the pieces to the puzzle in terms of what's happening and what we need to do now, since we haven't been able to identify any listed known diseases, we're going to keep an eye on the population over the coming weeks and months.

"It's only through time that we'll be able to fully understand what the impact to the population might be.”

To try and understand the problem, staff from the Environment Agency and National Trust are collecting healthy crayfish from the Wansbeck and placing them in quarantine.

They will initially be kept in water tanks at the National Trust site Washington Hall.

Nick Allen, from the National Trust, said: “This quarantine site will enable us to keep an eye on them and see if any of those symptoms show.

"If they don't, we'll be able to move these healthy crayfish to some of our ark sites on the estate.

"The ark sites are areas where we move healthy crayfish to create new populations that are safe away from invasive species.”

Despite the deaths, there is still hope for the future.

Some of the females moved into quarantine are carrying eggs and have been moved to Northumberland Zoo for their offspring to be hatched and raised.

Kimberly Smart, from Northumberland Zoo, explained: “In captivity, there's less risk for predation. Also because there have been some with symptoms, if they can be reared here, they're less likely to get any symptoms either.

"So really, it's just to try and boost the population and make sure we've got healthy individuals hatching out for next year.”

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