It isn't known how the fungus (Aphanomyes astaci) has spread to the River Allen which holds 40% of the UK population and it could be that it will now spread to the remaining parts of the UK.
All 8,000 of the river’s white-clawed crayfish are forecast to perish at the hands of the plague, a fungal disease carried by the larger Signal Crayfish from America, which is immune to it. Matt Shardlow, head of the Buglife insect charity, said: “Generally there’s no coming back once the plague arrives and I think it means we’re looking at the imminent end of the species across the south west,” adding that there is a real danger it could eventually spread across the whole country.
The white-clawed crayfish is the UK’s only native crayfish species. Other populations exist in the UK in areas such as the Midlands and East Anglia, but numbers are sparse and traditional strongholds in the Peak District and Ribble river in the North West have been almost wiped out. The species is on the endangered list.
The spread of the disease to the River Allen will accelerate the decline of the species, which is already estimated to have tumbled by 95 per cent since its peak. Once the disease infects crayfish, they are typically killed within weeks.Signal crayfish were brought to the UK in the 1970s, with many escaping into waterways through canals and some released into water courses because they can be fished for their tails. Their damage has been intensified by the ease with which they spread through waterways.