Tori lines, also called streamer lines, act as a scarecrow to deter seabirds from attacking the baited hooks off longlines, explained Ministry for Primary Industries national manager of fisheries compliance Steve Ham.
"All commercial fishers have a responsibility to take these practical measures to minimise the chance of harming seabirds," he said.
"Ignoring these important regulations not only threatens seabirds but also threatens the reputation of the commercial fishing industry which largely follows the rules."
He said the sentence should send a strong message to other commercial fishers that it's simply not worth the risk to intentionally disregard these regulations.
MPI encourages people to report suspected illegal activity through the ministry's 0800 4 POACHER number (0800 47 62 24).