The fox that wasn’t there?

Yet finding very few scats could also mean that our capacity to detect scats is extremely low, meaning that there might be a lot more undetected foxes out there and eradication indeed looks totally impossible. Alternatively there is something amiss, unexpected or fishy going on.

Recently a fox scat turned up on Bruny Island some 50km south of Hobart, suggesting that a fox had taken a boat ride or had swum much further than is typical for foxes (across the d'Entrecasteau Channel). Such an anomaly seems to me to be an indication that we should be urgently double-checking our procedures and assumptions to ensure the scat-DNA data is telling us what we assume it is.

Some critics have not been backward in suggesting that fox scats have been planted in Tasmania or the technique is faulty, perhaps in ways we do not yet know. It’s not nice to hear such claims, but nonetheless they remain valid scepticism until irrefutable contrary evidence is provided.

Yet the individuals who made claims of possible fraud were given the equivalent of a public cyber-flogging by Tony Peacock, the CEO of the Invasive Animals Cooperative Research Centre, who wrote an extraordinary on-line piece that pilloried the very suggestion.

But no one is actually finding fox poo in a Tasmanian paddock in any conventional sense. Instead, people are sending 1,000s of possible fox scats to Canberra for a DNA test and only there is it determined to be from a fox or not - 56 have been positive.

More than a few criminal court cases have collapsed not because DNA-based investigation techniques are faulted or anyone seriously questions the science behind them. Why they collapse is generally because unless you can prove “beyond reasonable doubt” that your entire chain of procedures from sample collection, analysis and until conclusion is beyond manipulation or contamination, you have potentially tainted knowledge.

You may well be beyond criticism, but no scientist is going to take your word for it. The best way to prove it is to use independent review and oversight as scientists must, not snarling at critics from within a closed shop.

A scientist or bureaucrat who takes, directs or influences public money for projects they are intimately involved in is disqualified from advertising themselves as objective and independent in the defence of their own vested interests. This is why science has a process of often anonymous and always independent “peer review”. Scientists get it wrong all the time and it is only by submitting to criticism that errors are found.

So, what is the way forward? Simple, we need some irrefutable evidence, or something close to it and we need it now. The scat-DNA technique can be this irrefutable evidence if we are prepared to go the distance. If the present fox scat-DNA results are correct and support other much less certain evidence it signals the depressing conclusion that foxes cannot be eradicated from Tasmania. So there is a lot riding on this.

Presently we don’t have irrefutable evidence, because some things with the scat-DNA data just don’t add up. From all the current evidence taken together there is dichotomy on offer so you can validly choose to believe that either foxes abound in Tasmania or believe that there is no absolutely convincing evidence that a breeding population of foxes exists.

After a decade, for this saga to be so short on knowledge it is a painful demonstration of how nearly $40 million has bought so little good science.

We need an independent scientific review of the entire application of the scat-DNA technique - and I do mean independent and scientific - look the words up if you’re not sure.