MPI risk assessment of trout eating mice poisoned by 1080
IntroductionThe Ministry for Primary Industries assessed in 2014 that trout caught after aerial 1080 pest control that may have eaten poisoned mice, did not pose a food safety risk.
MPI assessed research by the Cawthron Institute into the uptake and breakdown of 1080 in rainbow trout. DOC commissioned this research in response to concerns raised by anglers.
MPI found that 1080 levels in trout flesh fell well short of breaching international standards for human health. The trout were force-fed 1080 gel in the laboratory to reach these levels.
The assessment also stated that the peak 1080 levels were a 'gross over-estimate' of any 1080 residue likely to be found in wild trout.
Read the MPI assessment: How safe is trout to eat if caught in areas where 1080 has been dropped?
The Cawthron Institute also confirmed that the 1080 dosage in the trial was higher than what fish could have got from mice in the wild.
Download the report: 1080 uptake and elimination in rainbow trout (PDF, 2,26K).
DOC has welcomed the findings that trout caught after 1080 pest control do not pose a food safety risk to anglers.
DOC is working with Fish & Game to provide information to anglers on the issue and also maps and details about upcoming 1080 operations.
Background to trout and 1080 research
DOC commissioned research on the effects of aerial 1080 pest control on trout after anglers raised concerns in early 2014.
Trout eat mice in the wild and anglers were concerned about possible risks from fish eating 1080-tainted mice.
DOC worked with Fish & Game New Zealand and the New Zealand Federation of Freshwater Anglers on this issue. Together we developed a research brief to assess the impact of trout eating poisoned mice after 1080 treatment.
It is difficult to study the effect of 1080 on trout in the wild. Instead, a laboratory study was used to simulate what would happen if trout ate a large number of poisoned mice.
The Cawthron Institute carried out laboratory trials. This involved force feeding trout high levels of 1080 to model its uptake and breakdown in its flesh.
The trout in the experiment remained in good health throughout the trial and showed no ill effects from the poison.
The force-fed trout took up low amounts of 1080 into their flesh and this broke down over time.
DOC referred these results to MPI for an evaluation of the food safety aspects, as referred to above.