With invasive species the hot topic this leaflet my be helpful to anglers, available from the main bodies covering rivers and angling.
The central message is to anglers who fish more than one water:
Clean, check and dry your equipment carefully when moving from one water to another, diseases eggs and small creatures can attach them selves to your equipment, rods, lines and of course waders.
Anglers may feel that we are able to achieve very little but by helping to slow the spread on our own river and avoid transfer onto other waters we can do something. We may not be able to turn back the clock but we can at least slow progress and protect waters which are not yet infected/inhabitted.