Sodium fluoroacetate (1080) residues in muscle and liver of free-ranging feral pigs, poisoned with 1080-treated grain in a range of habitats, were determined. The incidence of vomiting, and the degradation of poisoned carcasses were also monitored. The maximum recorded concentrations in muscle (n = 79) and liver (n = 16) were 2.42 and 4.28 µg g?1 tissue, respectively. Mean (±s.d.) concentrations were 0.702 ± 0.535 and 0.635 ± 1.091 µg g?1, respectively. Muscle concentration in pigs sampled within 24 h of death were similar between those pigs poisoned with wheat (0.993 µg g?1, n = 21) and malted barley (1.012 µg g?1, n = 20) (P > 0.05), but muscle residues may have been lower in those pigs poisoned with lupin bait (0.178 µg g?1, n = 3). Muscle concentrations were also lower in those pigs sampled 24?48 h after death (0.481 µg g?1, n = 13) (P = 0.004). There were no differences between the sexes (northern rangeland: mean, females 0.883, males 0.869 µg g?1; agricultural: mean, 0.420 and 0.324 µg g?1) (P > 0.05), but adult pigs had lower muscle concentrations than did non-adult pigs (P < 0.001). There was no evidence of vomiting by any recovered poisoned pigs (n = 85), and all but one stomach contained substantial amounts of bait and other foods. Scavengers (mainly raptors) rapidly consumed poisoned pigs weighing <16 kg, within 2 days with no apparent ill-effects. Poisoned adults (?25 kg) were scavenged less frequently but, because of microbial action and the activity of invertebrates (e.g. fly larvae), these pigs were degraded within 7?10 days (i.e. no longer represented a potential food source for vertebrates). The levels of residues recorded were such that 1080-poisoned pig carcasses pose little potential risk to the long-term viability of non-target species.
|Author||Laurie E. Twigg, Tim Lowe and Gary Martin|
|Secondary title||Wildlife Research|
|Institution||Department of Agriculture, WA|
|Department||Vertebrate Pest Research Section|
|Control method||1080 (sodium monofluoroacetate)|