"We'd like to remind people that they should always be motivated by collecting for a feed rather than greed, and that it's an offence to buy seafood from an unlicensed source," he added.
"Buying fish this way is also a food safety risk, particularly in respect of the oysters, given that commercial oyster farms in the Bay of Islands were closed recently due to high rainfall."
The man would face charges under the Fisheries Act, and his boat, nets and a vehicle had been seized.
Mr Rudsdale urged anyone who was unclear about the fishery rules, regulations and limits to go to www.mpi.govt.nz/travel-and-recreation/fishing/fishing-rules, or who witnessed or knew of suspicious fishing activity to call 0800 4 POACHER (0800 447-6224).