Is 1080 Harmless to Fish?
The Parliamentary Commissioner for the Environment’s report on 1080 poison (Wright, 2011) claimed that effects of 1080 on populations of eels, koura and bullies had been studied (by Suren & Lambert, 2006) and that no effect on any of the fish was found.
Suren & Lambert’s experiment actually found that a large number of 1080 baits placed in bags in small flowing streams did not kill individuals of 3 species of fish held in cages either 10m or 100m downstream, within 4 days. In the experiment some of the cages were stolen, many fish escaped, and some mortality was attributed to high rainfall.
The experiment did not show that 1080 baits landing in streams do not affect fish. Fish would normally be able to feed on the submerged baits, contaminated detritus, plants and invertebrates around the baits. 1080 is known to adsorb extremely readily onto cellulosic structures (Hilton et al., 1969) so the toxin may remain close to the baits. Any effects on fish may take a long time to become apparent, for example, lizards took three weeks to die after being exposed to 1080 (ERMA 2007, Agency App. C). Flow rates in many areas where baits land may be much lower than in Suren & Lambert’s study, for example in small streams, in pools, and among weeds, leading to far higher 1080 concentrations in the water than those studied.
No attempt to investigate sub-lethal effects on fish was made by Suren & Lambert (2006). 1080 in small chronic or sublethal one-off doses has been found to be harmful to a vast range of organisms including microbes, plants, invertebrates, mammals, birds and lizards. Effects include damaged organs, impaired reproduction, growth and embryonic development (ERMA 2007, Agency Apps. B and C.).
There are indications of sub-lethal effects on fish among the very limited studies that have been done:
“significantly greater weight loss occurred in eels exposed to 1080 compared to those that were not”…”the sub-lethal concentrations of 1080 in the water may have been sufficient to inhibit eel metabolism”…”sub-lethal 1080 exposure presented to eels through ingestion of contaminated possum may have been sufficient to temporarily inhibit eel metabolism” (Lyver et al., 2005)
“96-hour [exposure of Rainbow trout, half of individuals dead at] 54 mg/l, sub-lethal effects on survivors – not specified” (ERMA Agency, Appendix C)
“Almost all trout (except for four) had condition factors indicative of fair to excellent condition at the end of the exposure time” (Champeau et al., 2014).
“morphological changes, induced by SMFA [sodium monofluoroacetate] were also investigated in the hepatoma fish cell line…changes were detected after 24 h exposure to 1mM…morphological changes, induced by SMFA, were also investigated in RTG-2 cells…alterations were detected from 1mM at 24h…The most out-standing alterations were the development of hydropic degeneration of the cytoplasm as a result of the energetic deficit produced by the SMFA, loss of cells and death mainly by necrosis but also by apoptosis” (Zurita et al., 2007).
Fish may also be affected by 1080 poisoning of their habitat, for example cover, water quality and food supply. There is massive variability in sensitivity to 1080 between organisms*, and although there is very limited information in general, species of aquatic plants (algae, duckweed), aquatic invertebrates (mosquito larvae and Daphnia magna) and bacteria in freshwater sediments have all been identified as sensitive to 1080 (ERMA 2007, Agency App. C.; Applicants’ References; Zurita et al., 2007). In both Suren & Lambert’s 2006 study and an earlier one (Suren & Lambert, 2002), effects of 1080 on populations of aquatic invertebrates were found but dismissed.
The feeding behaviour of only one invertebrate, koura, has been investigated around baits, and these animals preferred them over other foods (Suren & Lambert, 2006). Invertebrates take many hours to die and during this time can become very toxic as they continue to feed (eg 1080 residues in cave weta of 130mg/kg were found, ERMA Agency Appendix N).
Aquatic plants convert 1080 poison into the extremely toxic compound fluorocitrate, yet the environmental effects of this have not been studied (ERMA 2007, Appendix C.).
*”predicting the toxicity of 1080 to an untested species from data even on closely related species is difficult given the variations in response across and within taxonomic groupings”, ERMA Agency App. C p 391.)
Agency App. B, C, E, N, Applicants’ References: Environmental Risk Management Authority’s Assessment of 1080, 2007, Agency’s Appendices and Applicants’ References.
Champeau, O., Knight, B., Tremblay, L. 2014. 1080 uptake and elimination in the rainbow trout. Cawthron Institute report no. 2611: Cawthron Institute, Nelson.
Hilton, H., Yuen, Q., Nomura, N., 1969. Apsorption of monofluoroacetate -2C ion and its translocation in sugarcane. Journal of Agricultural Science and Food Chemistry 17: 131-134.
Lyver, P.O’B, Ataria, J., Trought, K., Fisher, P., 2005. Sodium fluoroacetate (1080) residues in longfin eels, Anguilla dieffenbachia, following exposure to contaminated water and food. NZ Marine and Freshwater Research 39: 1243-1252.
Suren, A.M., Lambert, P., 2002. Monitoring of streams in the Haupiri forests after 1080 aerial drops. NIWA client report CHC02/ 38: 17.
Suren, A., Lambert, P., 2006. Do toxic baits containing sodium fluoroacetate (1080) affect fish and invertebrate communities when they fall into streams? NZ J Marine and Freshwater Research 40: 531-546.
Wright, J, 2011. Evaluating the use of 1080: Predators, poisons and silent forests. Parliamentary Commissioner for the Environment, Wellington. 85 pp.
Zurita, J.L., Jos, A., Camean, A.M., Salguero, M., Lopez-Artiguez, M., Repetto, G., 2007. Excotoxiclogical evaluation of sodium fluoroacetate on aquatic organisms and the effects on two fish cell lines. Chemosphere 67: 1-2