MPI planned "Operation River" to target black market activity in the Hawke's Bay/Mahia area and used a special duties officer who became involved in the illegal trading of fish.
The operation uncovered illegal trading in 1.8 tonnes of paua (shell on) and 600 crayfish and finished in September last year when fishery officers executing 22 search warrants across the region.
Six other people have been dealt with by the court on charges of illegally selling fish from Operation River.
They have received a range of sentences including prison, community detention, community work, $15,000 in fines and forfeiture of vehicles and cell phones and one ban from all fishing activity.
Two people have been charged with illegally selling meat as part of Operation River and the investigation into related activity of a commercial fishing company is ongoing.
MPI encourages people to report any suspicious fishing activity to 0800 4 POACHER (0800 476 224). All calls are confidential.