Editorial: Eco setback for Fiordland

00:22, Jul 29 2013

It was always on the cards that snotty old didymo would cross the mountains and spread to Fiordland's wild west.

The Department of Conservation, Fish & Game, iwi and everyone else are entitled to their naked dismay at the news this wretched stuff has been found deep in purest Fiordland, in the Large Burn valley.

Fending off the spread was always likely to be a case of buying time.

Retrospective reports suggest the Mararoa River had didymo as early as 2001, but it was not until 2004 that it presented itself in full-blown, unlovely fashion. Since then, the Southland side of the Southern Alps has been living with those algal blooms that cast a mat on river floors to mess up the aquatic ecosystem, then develop a nasty toilet-paper aesthetic in their dead form.

The substance visible to the human eye is a veritable city of the real stuff - a microscopic aquatic plant small enough to exist unseen in a river and to be spread in a single droplet of water in a damp piece of fishing or hunting gear.

It has taken a brave campaign to fend off the spread as long as this. As recently as March, DOC was praising anglers and hunters, tourists as well as locals, for the diligence of the buy- in to the need for clean gear certificates before entering the area to fish, and their acceptance of the "Clean, Check and Dry" campaign.


On top of that, there had been satisfaction all the heavy rain and flooding at the very start of the year had led to water flows that flush and strip the pest from riverbeds and disrupt its growth.

There were, of course, those who regarded the whole business as futile, given that birds and other creatures could spread didymo. However, scientific wisdom has been that humans have always been the biggest risk, as there is a strong correlation between didymo finds and recreational river use and infestations, but none implicating bird nesting areas or colonies.

This is no time to give up the human campaign, nor to go through the motions in a fatalistic half-hearted manner. The more we do so, the more rampant the spread of didymo will be and the more severe the impact on those treasured parts of Fiordland.

You can live with didymo, if you really must. In time, superior ways to confront it might be found. Between now and then, it says much about us how we choose to react to adversities such as this.

The same goes for the other pieces of bad ecological news that have emerged in recent times. The campaign to reintroduce kokako to Secretary Island appears to have failed, at least in its latest incarnation. North Island birds were introduced there three years ago, in a campaign partnering DOC and the Fiordland Lobster Company. It was a noble try, but has apparently been confounded by a spike in stoat numbers in Fiordland, a small number of juveniles having swum out to Secretary. That is a great shame, and one which highlights yet again the need for significant pest control in remote areas.

Inevitably, this knockback will raise questions about whether the island is too close to the mainland to form a sanctuary, although there is the example of Stewart Island's near neighbours Ulva Island, an open sanctuary alive with birdsong, and Codfish Island, home to a recovery programme crucial to the survival of the kakapo.

As things stand, it appears reducing stoat numbers is the next step for any restart - which, of course, brings us back to the need for, and difficulties of, pest control in the wilds of Fiordland, where access is so difficult.

The Southland Times