Police and river bailiffs have joined forces to hook poachers targeting north-east rivers.
Two people have already been warned after they were caught fishing without permits on the River Deveron, near Banff.
Officers spent Wednesday and Thursday nights searching for illegal anglers as part of Operation Salmo.
Last night, police constable Paul Geddes said the criminals were jeopardising the environment and the livelihoods of large numbers of locals.
He said police and water bailiffs had teamed up on patrols in specific locations after receiving information about individuals and groups poaching salmon – and warned further patrols would follow until the problem was wiped out.
“Legitimate angling contributes greatly to local communities and economies and many people rely on visiting anglers for their livelihood,” he said.
“The actions of a few individuals can ruin the reputation of an area and lessen the attraction for visitors. We want people to come to the area and enjoy what is on offer but to do so responsibly.
“Threats to our natural habitat through criminal activity are not acceptable.”
Malcolm Hay, chairman of the River Deveron District Salmon Fishery Board, welcomed the initiative.
“I am delighted that the damaging wildlife crime of salmon poaching is being taken so seriously by the police,” he said.
“With legitimate angling interests working on a virtual 100% catch and release basis, it is obviously hugely important for our fragile stocks of salmon and sea trout that indiscriminate killing by criminals is halted.
“The River Deveron District Salmon Fishery Board is pleased to be able to co-operate with and support wildlife crime officers in their efforts to eradicate this illegal activity.”
Members of the public are urged to call police on 101 or Crimestoppers on 0800 555 111 if they are aware of crimes taking place on their local rivers.