Fisheries officers seized almost 400 illegally caught paua from recreational fishers in the Wellington region over the weekend.
Three groups of divers now face prosecution for collecting excess and undersized paua and excess mussels.
The prosecutions came as officers boarded more than 30 recreational vessels and spoke to more than 200 people in Wellington, Kapiti and Wairarapa.
"One of the groups had in excess of 290 paua. The vehicle and dive gear used in the alleged offending were seized," Ministry for Primary Industries district compliance manager Mike Green said.
"Some of the people we caught were experienced divers who know the rules but chose to flout them. There's no excuse for that."
"The rules around catch and size limits for paua and shellfish are clear."
"People who insist on taking excess and under-sized paua are depleting stocks for future generations."