The post-truth Trump phenomenon is spreading to New Zealand. Over the summer break untruths about the alleged poor state of this country's fish stocks were published as if they were gospel.

The fact New Zealand has been rated among the world’s top five best managed fisheries was conveniently ignored.

So why do people cherry pick facts when it comes to science?

A study by US researchers, presented last week at the Society for Personality and Social Psychology annual convention in San Antonio, Texas, found people treat facts as more relevant when they support their own opinions.

Simply focussing on the evidence and data is not enough to change someone’s mind.

People think more like lawyers than scientists when it comes to facts, which means they cherry pick those that back up what they already believe to be true, according to one of the study’s researchers, Troy Campbell from the University of Oregon.

“We find that people will take a flight from facts to protect all kinds of belief, including their religious belief, their political beliefs and even simply personal beliefs,” he said.

The researchers have coined the term “anti-enlightenment movement” for those who reject scientific consensus.

Thus, Forest & Bird, quoting unnamed “marine scientists” and “best available science” continues to insist it knows more about sustainable fishing than all the fisheries scientists and all those who make their living from the sea.

Massey University academic Dr Mike Joy, who has done good work in highlighting water quality issues, let himself down in an article published by Fairfax where he gave weight to F&B’s so-called best fish guide.

The New Zealand Herald allowed Seafood NZ to put the record straight this week in both its opinion pages and Bite food magazine.

Writer Gerard Hindmarsh was at it too.

In a nostalgic article on Stuff on the history of the wild, remote Whanganui (Westhaven) Inlet on the coast to the west of Golden Bay, he cited rich fishing in the past by his family in the vast inlet and lamented what had been lost.

“Reliable estimates put most of our fish species at around five percent of original biomass,” he claimed.

What reliable estimates?

That statement is complete and utter rubbish, a beacon for the anti-enlightenment, post-truth brigade.

My family, too, is familiar with Whanganui Inlet.

We fished it in the late 1960s and 70s but it was never the angling El Dorado some would have it.

We did catch a whopper snapper once that was feeding around a power pole in the shallows at the head of the inlet. But despite trudging miles to the entrance, or surf casting the flats as the tide moved in, we rarely caught more than the occasional dogfish and kahawai, sting rays and a lot of stinging sand courtesy of the predominant shrieking westerlies.

The weather was so much better then, of course, the summers were longer and everyone caught mountains of fish every time they went out.

That’s the popular narrative anyway.

I happened to be at Whanganui when visiting Golden Bay last month and stopped to talk to recreational fishers in two boats who had an impressive haul of groper, big blue cod and crays. Admittedly, they had gone out through the entrance into the Tasman Sea but said this was a standard catch.

And the snapper fishing in the Tasman region this summer has been “red hot”, one of the best seasons in recent memory.

That is according to the February edition of New Zealand Fishing News, the recreational fishers’ bible.

Another inconvenient truth for some is that annual reviews of New Zealand fish stocks assessed by Ministry for Primary Industries scientists show 96.8 percent of our catch is from stocks that are sustainable.

Way back in 2003, Damien O’Connor, then a minister in the Clark Government, addressed an international conference on the governance and management of deepsea fisheries in Wellington.

He challenged environmental NGOs to maintain their credibility by using accurate information and giving credit where it was due. He cited consumer choice cards that urged consumers to avoid products from so-called unsustainable fisheries.

“Classifying all products from a particular species as bad or unsustainable simply is not good enough. It is misleading.

“Environmental NGOs can work against industries and government to raise awareness of issues and they can work with industries and government to develop solutions.

“Unfortunately, some NGOs over-use the first, oppositional mode of operation. The result is that they are seen less as fair critics of a decision than as reliable pessimists. Far better, surely, to deploy the twin tools of credit where it is due and criticism where it is deserved.”

Damien O’Connor’s challenge of 14 years ago is still as valid today.