1080 fish risk low: Doc

Ian Hadland.
Ian Hadland.
Concerns about the health risk from eating trout that have eaten mice contaminated with 1080 should not stop anglers enjoying the new fishing season, Fish and Game Otago says.

Doc, in conjunction with Fish and Game and the New Zealand Federation of Freshwater Anglers, commissioned research into the effects of trout eating mice after aerial 1080 pest-control operations had been carried out.

The Cawthron Institute carried out independent laboratory tests on trout in tanks dosed with high levels of 1080 and the fish remained in good health.

They did take up low levels of 1080, but this broke down naturally over a number of days.

At the levels assessed during the trial, an average-sized adult would need to eat several tonnes of affected trout flesh in one serving to have a 50% chance of a fatal dose.

In Otago, Doc's Battle for the Birds 1080 operations have been carried out around the headwaters of the Wanaka and Wakatipu tributaries.

Operations in the catchments of the Young, Wilkin, Makarora and Matukituki Rivers are still to be completed.

1080 drops have also been confirmed for the Catlins and Blue Mountains.

Fish and Game Otago operations manager Ian Hadland said the 1080 was an issue only for back-country anglers who wanted to kill and eat trout, but about 90% of anglers released the trout back into rivers.

''So we can't see many anglers being impacted by these results and the operations.''

There could also be some benefits to anglers, as during the last beech mast, trout grew to trophy size ''really quickly, having dined out on mice which had fallen into the water''.

''Anglers who fished these areas had some wonderful fishing.''

While the risk of harm was ''very low'', the reported levels of 1080 in the flesh were above a guideline for human health so Doc was right to take a zero-risk approach and had a duty to warn.

The risk was further reduced by the fact 1080 baits were not laid within 50m of a major river and the home range of mice was less than 25m.

Mr Hadland urged anglers to take a common-sense approach.

''Just as you wouldn't harvest a wild deer and eat it within a couple weeks of a poison operation, the same should probably apply for other wildlife, including trout.''

Doc director-general Lou Sanson said Doc would refer the initial report to the relevant health and food safety authorities for their assessment and, in the meantime, stood by its position anglers were at little risk from aerial 1080 pest-control operations.

''These are preliminary laboratory results and further work is required to assess the risk of wild trout eating potentially contaminated mice in field conditions.

''If anglers are concerned, they can take a ''zero risk'' approach by not eating fish caught in catchments where there have been aerial 1080 operations.''

 

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