Dr Mike Joy: Clean, green New Zealand? Yeah, nah!

What we're seeing with native fish and the decline in our freshwater quality is a clear and urgent crisis. Photo / File

COMMENT: Congratulations, New Zealand, we're number one. No country in the developed world is trashing its rivers as fast or as thoroughly as we are.

When we first assessed the threat status of our native freshwater fish in the early 1990s (before that we just assumed they were fine because we're a clean, green nation, right?), it turned out 22 per cent were either threatened or at risk.

That's one species in five. An appalling figure, but old news. In 2018 the figure is 74 per cent. We've gone from one species out of every five being in trouble to a situation where three species out of four are staring extinction in the face, and we've done it in a generation.

This makes us by far the worst of the developed nations for fish species health. As bad as that is in itself, the central truth of ecology is that things never exist in isolation. He tu te Pahu, He tu te Tai (If the dolphin is well, our coasts are well). Same with fish: They're either top of the aquatic food webs in our rivers, or close to it, so they're ideal indicators of the health of freshwater ecosystems.

What that tells us in 2018 is that New Zealand's freshwater systems are in awful shape and getting worse fast. Our grandchildren won't be swimming in our rivers, and there won't be native fish in them either, unless we make changes.

You would think government would be all over this situation, given how long we've known about it and how quickly it's worsening. Guess how many native species are specifically protected under the Freshwater Fisheries Act? One.

This would at least be good news for that one species, except that it's the grayling, and the grayling had been extinct for five decades when the law was passed. Mind you, the law does grant protection to introduced fish such as trout and salmon. Imagine if we protected goats and deer instead of kiwi and kereru.

All other native fish species have legal protection if they are not used for "human consumption or scientific purposes". In practice this translates to zero protection.

Freshwater crayfish: threatened. We eat them. Freshwater mussels: threatened. We eat them. We harvest five species for fun and profit under the name "whitebait" - the īnanga, the kōaro, the banded kōkopu, the giant kōkopu and the shortjaw kōkopu. Of these, only the banded kōkopu is not threatened.

Any time you eat a whitebait fritter, you're eating the juveniles of native species that in all likelihood won't be around much longer. Basically, you're eating kiwi chicks. Our endemic longfin eel, classified as "in decline", we commercially harvested and export.

Meanwhile, DoC, the agency charged with regulating whitebait, has been missing in action. The rules governing whitebaiting have not been meaningfully changed since their inception, though they're based on out-of-date science and would offer inadequate protection even if they were properly enforced, which they're not.

It is strictly forbidden to take whitebait at night, for instance, a rule which was put in place to ensure some of these juveniles make it up the river safely. Whitebait don't move at night. We've known this for decades.

What we're seeing with native fish and the decline in our freshwater quality is a clear and urgent crisis. When you look at the statistics on species decline, it's pretty clear they're bad everywhere outside of the conservation estate, but worse anywhere we're practising intensive farming.

We need to match land use to soil types and slopes to control runoff. We need major reductions in intensity, and we need to look at the way local councils are charged with protecting the economy and environment when they apply the Resource Management Act.

We've been trying to have our cake and eat it. We need to stop or soon there won't even be crumbs left.

• Dr Mike Joy is a senior researcher at the Institute for Governance and Policy Studies, Victoria University of Wellington.