Fish & Game is concerned at the dangerous behaviour of those poaching fish in Rotorua - including one man who threatened to stab a Fish & Game officer when he was caught.
Eastern Region Fish and Game officer Anthony van Dorp said there had been a spate of poaching incidents in the city recently with one incident being "extremely serious".
"In the worst of eight separate incidents, a man found fishing illegally in the upper Utuhina Stream threatened to stab a Fish & Game officer," he said.
He said the Fish & Game officer had spotted the man using an illegal fishing method in an area of water which was closed during the trout spawning season.
"When he approached, the man became very aggressive and belligerent, and the threat was repeated twice - with the poacher's body language also very threatening," he said.
"After he'd refused requests to co-operate, the man ran off."
Mr van Dorp said the officer involved was praised for his handling of the incident.
"He withdrew from the encounter at an early stage following staff safety training procedures to the letter, and alerted police who are now investigating."
He said Fish & Game was appealing to anyone who was in the upper Utuhina area on Saturday afternoon who may have seen the poacher, thought to be in his early 20s, to let them know.
Mr van Dorp said a man was recently sentenced in the Rotorua District Court to 250 hours community work for his part in taking 25 trout from a spawning stream, while an associate of his was given 150 hours community work.
"In one of the other incidents, on Sunday, a man was caught with 13 rainbow trout taken from a Rotorua closed spawning stream.
"He is facing charges and officers are following up on two other people believed to have been involved," he said.
"None of the weekend incidents prompted any calls from the public to Eastern Fish & Game's 0800 POACHING line, which is quite unusual and concerning so we do take this opportunity to remind the public of the number and its purpose, to protect the district's vulnerable spawning streams in particular."