Howell was convicted for his role in the black market ring on October 18.
Ministry for Primary Industries spokesman Brendon Mikkelsen said they had been covertly monitoring the trawler's activities for two months in an operation codenamed Operation Waterfowl.
It was estimated that 13 tonnes of catch - primarily snapper - had been sold to the black market in Tauranga, Hamilton and Auckland.
Offenders were detected at every stage of the operation, from commercial fishing operators and truck drivers to receivers of the illegal fish, including fish shops and takeaway businesses, Mr Mikkelsen said.
Western Bay Seafoods Limited, Hira Cyril Noble, Jason Lionel Abbott, Lay Queen Lim and Tuan Tran were also convicted in the operation.
Lee's jail sentence was a real deterrent for anyone considering offending on a commercial scale, Mr Mikkelsen said.
"We're not talking about a couple bins of fish going astray here. This was 13 tonnes of one of New Zealand's prime table fish essentially being stolen from the rest of the fishing community.
"The actions of these offenders have threatened the integrity of the Quota Management System.''
It also gave them an unfair commercial advantage over law-abiding operators and threatened the snapper fishery in the Bay of Plenty, Mr Mikkelsen said.
Fishing industry operators and non-commercial fishermen are encouraged to report suspected illegal activity through the ministry's hotline 0800 4 Poacher (0800 4 76224).