AgroPages-Alligator weed invading Waikato River-Agricultural news

Alligator weed, with the paler leaves, is threatening internationally recognised wetlands and part of the country’s longest river.

There's a war raging in Waikato and Conservation Department ranger Chris Annandale is on the losing side.

"It's an uphill battle," he says. "I don't know that we're ever going to win it."

The powerful foreign force takes its name from a carnivorous reptile and will choke the region's rivers and wetlands given half a chance.

Alligator weed is near the top on the most unwanted list of the world's weeds and is threatening to destroy the Whangamarino Wetland near Meremere. It's one of six New Zealand wetlands listed as internationally important under the Ramsar Convention, an international treaty for the conservation and sustainable utilisation of wetlands.

But there's one impossible idea that could swing the war in Mr Annandale's favour.

Right now, he, his DOC colleagues and ally Waikato Regional Council are damned if they spray herbicides on it and damned if they don't.

Mr Annandale is sitting at the helm of a river boat on the lower Waikato, just days into the whitebait season, when he explains the predicament. "If we don't spray it and it takes over the entire river and buggers the whitebait fishery, then we're absolutely damned," he says.

"They use a big airboat [to spray] and it's really noisy and often some of the better times to spray are also prime nesting times. So it upsets duck shooters because the birds can't settle to nest properly. They have to come to terms with, if we don't, they can kiss goodbye the lower Waikato - it's that serious."

There's also concern about the effect the toxic sprays could have on aquatic life. There are already spots of the weed in the Whangamarino and the invasion locations have fuelled speculation that fragments could have been trans-ferred via com-mercial eel nets.

A single fragment will re-grow and start an infestation where it falls. So, what about trying to unite everyone who uses the lower Waikato and Whangamarino?

"The thought is there. But you try to deal with all these people . . . They're very individualistic - you have whitebaiters, duck shooters, eelers, mulleters, a whole sweep of people down here and each wants to keep what they're doing separate from the other."

The one thing they have in common is a reliance on the Waikato River for their lifeblood and leisure. The question then is, are they prepared to fight for it?