"The scientists are saying the fish numbers have recovered but not enough, and that the average size has gone down, but they never consult the guys who make their living off fishing and who know where and how the fish move around," Mr Hayes said.
He said a three-year scientific survey could not match 40 years of local knowledge of fish movements and trends.
It was well known that small fish stay inshore, especially in the Hauraki Gulf, and bigger fish move out deeper, he said.
It was also well known among commercial fishers that the "average" size was smaller because of the "enormous increase in the overall number of juveniles".
Based on that average size, the Ministry of Primary Industries looks set to slash the recreational snapper take within a few weeks. The Ministry has dropped a recommendation that commercial quotas also be cut.
Mr Hayes said while he supported recreational groups lobbying against cuts, he disagreed with assertions that snapper stocks were being depleted by "indiscriminate'' trawling methods.
Trawlers did not fish the same places as recreational fishers, and commercial operators without a sizeable ticket for snapper avoided catching them like the plague.
Snapper were not a well-paying haul unless operators held large quotas, and those were expensive, Mr Hayes said.
But there was no doubt that fewer fish were "coming out of the sea" than years ago, he said.
There are only three trawlers fishing full time out of Whangarei, down from 15 less than 20 years ago.