The snapper contained a tag – known as a passive integrated transponder (PIT) – that was implanted into the fish on 21 February 2002 by NIWA principal technician Derrick Parkinson, who incidentally still works at NIWA.

Thirty years of management informed by a raft of scientific research appears to now be paying dividends.In the Hauraki Gulf, commercial and recreational fishers are reporting improving catches, and NIWA scientists will soon be able to estimate whether the highly valued Hauraki Gulf snapper population is seeing a similar increase.

In the noise of the Sanford processing shed In Auckland, NIWA scientists Rikki Taylor and Darren Parsons are measuring hundreds of fish from a catch that has just landed as well as removing otoliths to be measured back at the laboratory.

“If you actually put your head underwater and take the time to listen, it's amazing what you'll hear,” Radford says.

People along the Kapiti and Wanganui coast may spot NIWA’s research vessel Kaharoa operating close to shore in the next few weeks as scientists carry out a survey of snapper, tarakihi, red gunard and John Dory.

Dr Morrison is leading a five-year MBIE Endeavour Fund research programme that he hopes will ultimately result in new options to assist in the future management of this species in the Hauraki Gulf and East Northland; as well as juvenile blue cod in the Marlborough Sounds.