Northumberland Zoo may have to quarantine endangered crayfish

It is currently surveying the River Wansbeck catchment to determine the extent of the outbreak.

Ms Edwards said everyone at the zoo had been relieved when they discovered crayfish plague was not behind the deaths.

The disease was fatal to white-clawed crayfish, she said, of which Northumberland had a particularly large population.

But the lack of answers behind the deaths was troubling, she added.

“If we don’t know what it is, we don’t know how to solve the problem,” she said.