The estuary is an important route to spawning grounds for salmon and sea trout which migrate up the River Dee.

A buy-out for legitimate "netsmen" aims to ensure no legally-taken Dee salmon are sold to hotels or fishmongers.

The environment agency and the Dee Fishery Association said illegal netting was having a significant effect on the migrating fish population in the estuary as it prevented many fish from reaching their spawning grounds. The agency's area manager David Edwell said: "Environmental crime is becoming increasingly unacceptable to people and using an intelligence-led approach is a very effective way to catch the offenders.