Report suspicious behaviour, says DEFA
Members of the public are being asked to help protect salmon and sea trout.
The Department of Environment, Food and Agriculture wants Manx residents to be able to recognise and report signs of suspicious behaviour.
DEFA says the signs of illegal activity include tyre marks going onto the beach, vehicles on the beach during the hours of darkness and lights on rivers.
Those caught breaching the law could face a range of penalties including a fine or confiscation of their fishing equipment and catch.
It's now illegal to fish for salmon and sea trout in Manx rivers until April 1st to allow fish to spawn undisturbed.
Anyone who sees something suspicious is being urged to report it to the Fisheries Directorate on 685857 or to their local police station.
Fisheries officers will be conducting night time patrols and working with the Isle of Man Constabulary.