On the 6th July we electric fished the Suckley Brook at Longley Green, Worcestershire as part of our routine sampling programme.
Sadly the results were abysmal, we caught 2 x 3 spined stickleback and 1 large eel in 100m stretch.
The reason? Signal crayfish, large and small. Every time we tuned the current on there they were. We caught and dispatched what we could but they appear to have decimated the watercourse as they’ve eaten much of the insect life and the fish fry leaving a very barren stretch.
This non-native species was first introduced to Britain in the 1970s and has spread to many of our rivers and streams. It out-competes our native white-clawed crayfish and, as our survey shows, can have serious impacts on the local freshwater ecology.
Unfortunately, the problems caused by signal crayfish were compounded at the survey location by overshading and heavy sedimentation caused by run-off from farmland within the catchment (both also common issues on lowland watercourses)