Analysis: 'Swimmability' only part of the grim freshwater story
Thursday, 27 April 2017
ANALYSIS: Another day, another report on the grim state of New Zealand's waterways.
If constant freshwater reports feel like a blur, it is because they say much the same thing: Our rivers are degraded, humans are the cause - and we need to do better.
The latest report, released on Thursday by the Ministry for the Environment and Statistics NZ, broke the mould.
Its focus was not river 'swimmability' for people. The agencies released official data about threats to our freshwater species.
**READ MORE:
* Any luck with the water, mate?**
The result was damning: nearly three quarters of our native freshwater fish are threatened by, or at risk of, extinction. A third of both freshwater plants and freshwater invertebrates are in the same category.
One fish species, the once-common grayling, is already extinct. It is not looking good for the other 39 species for which data was available.
In recent debates around water quality, 'swimmability' was the buzz word.
Swimmability, in itself, does not mean anything. It is not in the dictionary. There is no agreed-upon definition to argue about. It is a blank canvas for whoever is using the word.
We saw that in effect when the Government announced its Clean Water Package earlier this year. It said the 'wadeable' standard was no more. Ninety per cent of rivers and lakes would meet a new 'swimmable' standard by 2040, and 72 per cent already met that standard.
Of course, if you went to one of Canterbury's 'swimmable' rivers over summer, there may have been no water in it, or there were signs warning against swimming because of potentially toxic algae.
That's because the Government's measure of swimmability meant a site where E.coli levels were beneath a certain threshold for a certain period of time, a definition that clashed with opposing ideas.
As Secretary for the Environment Vicky Robertson said: 'there has been a strong focus on how swimmable our waterways are, but that is just part of the story'.
If you were measuring the health impacts of smog in a polluted city, you wouldn't test the lungs of a tourist who visited for a week. You'd look at a local who breathes the air 24/7.
Our obsession with swimmability as the measure for waterway health means we're measuring tourists, not locals. Our benchmark is how water quality affects someone who occasionally goes swimming, not the health of the aquatic life living in the water.
Swimmability puts humans at the centre of the debate, when we're one of several affected groups, whilst being entirely the cause.
As the report notes, the threats to freshwater species are an indicator for the threats to waterway health in general. They include nitrogen levels which promote algal blooms, degraded habitat through sedimentation, flows altered by dams and weirs, introduced pest species, among others.
Few of those factors are considered in the swimmability debate, but are just as much a part of the story.
'The implications for our freshwater species are really critical,' Robertson said.
'A lot of our native species are endemic. You don't find them anywhere else in the world. If we lose them, they are gone forever.'
Consider the lamprey, one of our threatened freshwater species. They are taonga to Maori and, like the tuatara, sometimes called a living fossil - a species unchanged over hundreds of millions of years.
Lamprey swam with dinosaurs and survived at least four mass extinctions, but, in New Zealand, the species may not survive us.
The same goes for the longfin eel, one of the most fascinating freshwater species in the world, or our multiple species of whitebait. All are threatened, and it is our fault.
For a long time, swimmability has been used as a proxy for water quality, but it is one without a baseline standard everyone agrees on.
The health of aquatic life should be easier to agree on. If there's one thing the latest freshwater report does that is worthy, it makes one fact undoubtedly clear: it's not just about us.