Trout Fishers advise Caution about 1080 Poison near Turangi
New Zealand Federation of Freshwater Anglers president and retired veterinarian Peter Trolove has cautioned against the proposed aerial 1080 drops near the lower Tongariro River.
While Dr Trolove is aware of the important role OSPRI has in controlling and eradicating bovine TB from NZ’s national stock herds and accepts the New Zealand Veterinary Association’s Policy Statement on the controversial use of 1080 in the absence of a better option, his own experience in South Westland is sobering.
Dr Trolove caught a trout whose alimentary tract lining was deeply stained by the tell-tale 1080 dye from a South Westland river.
“This trout appeared just as healthy as the dozen or so other trout I caught and released that day. I kept one trout to eat so I autopsied the fish to see what it had been eating. The dyed gut was a shock as it could only have come from direct ingestion of a 1080 pellet,” he recalled.
The local DOC office confirmed that there had been a 1080 drop “about three months previously.
A Cawthron Report, No. 2611, was unable to accurately determine the half-life of 1080 in trout flesh, but the tissue sampling revealed high levels of the toxin for at least 120 hours. The study said trout themselves were not affected by high levels of the toxin, but recommended further studies
“This is not surprising as the metabolic rate of a cold blooded animal is quite different to warm blooded ones,” explained Dr Trolove. “Elevated fright/flight hormones take several weeks to return to baseline levels and symptoms of toxicity from exposure to pollutants are likely to take much longer than the 96hour LC50 period typical of most studies.”
Dr Trolove said when toxic residues were found in exported game meat, MPI quickly developed a protocol where only licensed WARO operators with complete GPS records, could supply deer to processing plants for export. New Zealanders have always had a lower level of food security from our government authorities and are the default market when product does not meet the standards of our overseas client countries.
“The Putararu family that got “botulism” from eating wild pork from a 1080 poisoned area should be a wakeup call to all.”
DOC and Fish and Game studies have assumed that trout would only pick up 1080 via secondary poisoning from eating dead mice or other organisms, or contact from 1080 leaching into the water. These assumptions may not be true he said.
“I am now wary about taking trout from South Westland rivers and lakes, an area in which I spend a lot of time hunting and fishing. South Westland appears to be singled out for more than its fair share of blanket 1080 poisoning in the questionable “Battle for the Birds”. The loss of kiwi, morepork, kaka, keas, falcons, harrier hawks, plus many of the insect eating native birds is all too evident from my visits.”
Dr Trolove said he trusted his own observations rather than “dodgy DOC science” such as a recent paper suggesting there is no evidence of negative effects of aerial 1080 on deer in South Westland forests (NZ Journal of Ecology 2019, 43(2)) .
“I made a point of hunting the study area at the end of this year’s roar to find game trails and wallows overgrown and unused. The authors may not be aware that deer take a while to die when suffering from the effects of 1080 at which time they are no longer interested in concealment,“ he said.
Until there was credible evidence to the contrary, caution should be foremost in taking trout for food from 1080 poisoned catchments concluded Dr Trolove.