An investigation run from an office in Auckland promises to have a lasting impact on global fish stocks and conditions on board the boats which harvest valuable fish species.
The environmental group Greenpeace undertook the inquiry, which has led to a remarkable agreement with Thai Union, the world's largest canned tuna company, to address overfishing and labour abuse at sea.
Much of the credit for the deal rests with former police officer Tim McKinnel and his team.
McKinnel, whose dogged work exposed miscarriages of justice in the Teina Pora case, helped run the Greenpeace tuna campaign for the past few years. Its work delved into overfishing as well as the appalling conditions on boats endured by a largely migrant labour force.
McKinnel, who once worked with the police in south Auckland, remarked that while he had encountered unpleasant crime scenes in New Zealand, he was unprepared for the scale of exploitation in the global fishing industry. The inquiry ranged as far as West Africa and across the Indian Ocean to Thailand and landlocked Cambodia, a poor nation with a plentiful supply of desperate workers.