Trout and 1080

The Trout & 1080 Report.

The conclusions to this report are:

1. trout can uptake high levels of 1080 in their flesh without dying.

2. we don’t know how long it takes to leave the trout’s body but it is longer than 5 days.

CawRpt_2611_1080 in trout study

Here is the NZFFA’s position on trout and 1080….

The NZFFA was instrumental in getting the research on trout and 1080 undertaken.  Given that it is near impossible to work out the chances of a trout eating one or more mice which have consumed 1080 we focussed on a more attainable and equally valid point – how long is there any risk to anglers from eating secondarily poisoned trout.  To this end Cawthron constructed an experiment to gauge the time it would take for a trout to depurate (excrete and metabolise) 1080 from its system.  Given DoC’s poisoning programme we could then identify how long there would be a risk in any aerially poisoned catchment, irrespective of the unknown size of that risk.
Unfortunately, the results of the experiment were inconclusive as the experiment was not run long enough.  What we did see was that after three days the trout had taken up nearly 100% of the dose of 1080 into their muscle tissue and was still present after five days – the end of the experiment.  The levels peaked at 4,700 times the limits set out by the FSA for 1080 in food, albeit they state this applies to export food only (I do not not why this is the case).  Even allowing for the fact that the 1080 dose given to the trout was high – equivalent to 20-30 mice all having ingested an 12-18mg/kg body weight of 1080, simple extrapolation of the results leads us to believe that a trout having eaten one poisoned mice would present a health risk to humans.
DoC chose to present the results in terms of lethality to humans and hence their message that it was OK to eat trout because you wouldn’t die, whereas we are concerned as much with the effects on humans of sub-lethal doses, particularly as sub-lethal 1080 data on mallards shows vital organ damage and foetal deformities.  There is no research on sub-lethal doses to humans so we take a precautionary approach, a la National Poisons Centre.
So, in summary we recommend anglers DO NOT eat trout from 1080 areas.


Leave a Reply