a positive effect on the recovery of native skink and gecko populations. Killing rabbits and possums, which compete for food with skinks and geckos, may also have benefits. Fish Fish generally have very low sensitivity to 1080. Toxicity tests have been conducted in the US on bluegill sunfish, rainbow trout, and the freshwater invertebrate Daphnia magna. Tests at different 1080 concentrations on sunfish (for four days) and Daphnia (two days) showed that 1080 is "practically non-toxic" (a US EPA classification) to both these species. Rainbow trout were also tested over four days at four concentrations ranging from 39 to 170 mg 1080 per litre. From these results an LC50 (the concentration of 1080 per litre of water which theoretically kills 50% of the test fish) can be calculated. The LC50 for rainbow trout was calculated to be 54 mg 1080/litre – far in excess of any known concentration of 1080 found in water samples following 1080 aerial operations. Thus 1080 is unlikely to cause mortality in freshwater fish. Invertebrates Insects are susceptible to 1080 poisoning. Some field trials in New Zealand have shown that insect numbers can be temporarily reduced within 20 cm of toxic baits, but numbers return to normal levels within six days of the bait being removed. Other trials have found no evidence that insect communities are negatively affected. Another New Zealand study showed that wētā, native ants, and freshwater crayfish excrete 1080 within one to two weeks. There is also evidence that 1080 aerial operations in New Zealand can benefit invertebrate species. Both possums and rats are a serious threat to endemic invertebrates in New Zealand, where around 90 per cent of spiders and insects are endemic and have evolved without predatory mammals. In a study on the diet of brushtail possums, 47.5 per cent of possum faeces examined between January 1979 and June 1983 contained invertebrates, mostly insects. One possum can eat up to 60 endangered native land snails (Powelliphanta spp.) in one night. See also Fluoroacetamide Methyl fluoroacetate Fluoroethyl fluoroacetate Fluoroaspirin References Further reading External links Sodium fluoroacetate, CDC – NIOSH Pocket Guide to Chemical Hazards A report on the Western Shield project of the Department of Environment and Conservation (Western Australia), NatureBase (archived) Press release demanding the ban of 1080 use in Tasmanian forests (2004) wilderness.org.au (archived 2011) Notes on 1080 use for controlling predators in Idaho (archived) A review of the documentary