Quick Dips

Killing Time

There are plenty of ways of killing a possum, and Jenni Bennett who has just completed her MBA degree at Victoria University is familiar with most of them.

"I live in Makara and I've been killing them for twenty years," she says.

So what better topic for an MBA research paper than a cost-benefit analysis of the best way to get rid of New Zealand's estimated 70 million possums?

"About $58 million a year is being spent to control possums, mostly for TB control, but this is just a kind of holding operation, targeting specific areas," Jenni Bennett says. "There's no overall programme to tackle the problem nationwide. If there was, we might get the possum population down to just a few million."

Her work with computer models show this could possibly be done by starting at one end of New Zealand and working right through the country over a four-year period, reducing the possum population by 80%. And then starting over again and again.

"Unless an effective biological control is found, wiping them out altogether is impossible, but my research based on accepted models of possum control shows this method could reduce them to just a few million in 20 years."

Bennett says many cost-benefit studies have been done, but they have focussed on the killing itself, without quantifying the overall costs and benefits involved, such as increasing employment and safeguarding export markets.

"Obviously you have to use the right method for the terrain. Aerial drops of 1080 poison are the best for large areas not close to human habitation. That method is cheap and effective but it doesn't have many side benefits like job creation and training.

"On the other hand, shooting, trapping and on-the-ground poisoning are jobs that unemployed people can be trained in under schemes such as Task Force Green. It gives them self-esteem and work skills, and in some cases solves other problems by getting them off the streets, off dope and out of the courts and prisons.

Bennet claims the net present value of the shooting and trapping option wins out by several billion dollars over a 20-year period. Now she's seeking support for having departments such as Welfare, Justice and Employment involved in the decision-making on possum eradication and providing money for a training programme.