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Please ensure that you maintain high biosecurity standards when Riverfly monitoring by following Check, Clean, Dry

It was reported, in the November issue of Trout and Salmon magazine, that a Chinese mitten crab has been found in the River Ribble in Lancashire. The invasive non-native species (INNS) was recorded and photographed by an angler at Brockholes nature reserve, with positive idenfication being confirmed later by the Environment Agency. The Chinese mitten crab is an alert species meaning that all sightings should be reported immediately to your local Environment Agency contact and online via the GB Non-Native Species Secretariat (GBNNSS). GBNNSS information suggests this species is likely to impact native, benthic invertebrate populations in freshwater and marine systems, through predation and competition for space, and has the potential to outcompete the native white-clawed crayfish.

In addition to the Ribble Chinese mitten crab is established in the Rivers Thames, Medway and Ouse and has been recorded in other rivers throughout England and Wales, including the Tyne, Tamar and Dee and Southfields Reservoir near Castleford, Yorkshire.

Whenever you are at the river ARMI sampling, or fishing, etc., please be vigilant for this and other INNS and ensure that you record and report sightings as a matter of urgency. In addition, it is essential that good biosecurity is employed by following the CHECK, CLEAN, DRY protocols as outlined in your ARMI participant pack or online at