Police are looking for a man who poached 272 undersized paua in Hicks Bay on the East Coast.
The haul of shucked paua and a four-wheel drive vehicle were seized.
The driver of the 4WD, a youth under 14 years of age, was arrested but his adult companion is still on the run.
"We know who he is but police are still looking for him," said Ministry of Fisheries district compliance officer Tom Teneti. "He's a transient individual."
Mr Teneti says there were no words to express how he felt about the theft.
"You're robbing from the next generation. It impacts on the local community as well."
The shucked paua have been returned to the sea. Dead or alive, it is normal process to return stolen and undersize paua to the ecosystem, Mr Teneti said.