Authorities have cracked what they believe is a large scale black market fishing operation in Auckland and Tauranga.
Fishery officers in Tauranga seized a commercial fishing trawler, two refrigerated trucks and a large amount of cash.
The investigation began following a report from a recreational fisher who had found a large number of snapper dumped near Town Point, Maketu in September.
Fisheries' spokesman Brendon Mikkelsen told Newstalk ZB authorities were able to pinpoint a vessel and covertly monitored it for two months, mainly under the cover of darkness.
Mr Mikkelsen said the vessel is believed to have been involved in selling more than 12 tonnes of undeclared fish to buyers in Auckland and Tauranga.