Rate of exposure of a sentinel species, invasive American mink (Neovison vison) in Scotland, to anticoagulant rodenticides

Abstract

Anticoagulant rodenticides (ARs) are highly toxic compounds that are exclusively used for the control of rodent pests. Despite their defined use, they are nonetheless found in a large number of non-target species indicating widespread penetration of wildlife. Attempts to quantify the scale of problem are complicated by non-random sampling of individuals tested for AR contamination. The American mink (Neovison vison) is a wide ranging, non-native, generalist predator that is subject to wide scale control efforts in the UK. Exposure to eight ARs was determined in 99 mink trapped in NE Scotland, most of which were of known age. A high percentage (79%) of the animals had detectable residues of at least one AR, and more than 50% of the positive animals had two or more ARs. The most frequently detected compound was bromadiolone (75% of all animals tested), followed by difenacoum (53% of all mink), coumatetralyl (22%) and brodifacoum (9%). The probability of mink exposure to ARs increased by 4.5% per month of life, and was 1.7 times higher for mink caught in areas with a high, as opposed to a low, density of farms. The number of AR compounds acquired also increased with age and with farm density. No evidence was found for sexual differences in the concentration and number of ARs. The wide niche and dietary overlap of mink with several native carnivore species, and the fact that American mink are culled for conservation throughout Europe, suggest that this species may act as a sentinel species, and the application of these data to other native carnivores is discussed.

Prevalence of Anticoagulant Rodenticides in Feces of Wild Red Foxes (Vulpes Vulpes) in Norway

“…We did not find association between AR exposure and sex, which is in accordance with previous studies in red foxes (Tosh et al 2011) and other wild predators (Shore et al 2003;Elmeros et al 2011;Ruiz-Suárez et al 2016). However, sex differences in the extent of territory usage, with single male foxes having a larger home range than females, have been observed (Larivière and Pasitschniak-Arts 1996).…”

“…A similar lack of associations was observed in other carnivores, such as bobcats, weasels, and stoats (McDonald et al 1998;Serieys et al 2015). However, a correlation between AR exposure and increased age was found in American mink (Ruiz-Suárez et al 2016) and European polecats (Mustela putorius; Sainsbury et al 2018).…”

“…Predators can accumulate ARs through ingesting bait (primary exposure), by consuming poisoned prey (secondary exposure), or by ingesting prey secondarily exposed to ARs (tertiary exposure; Daniels 2013;Gabriel et al 2018). Wildlife studies in Europe and North America have shown 23-100% AR occurrence in liver samples from predators such as American mink (Neovison vison;Ruiz-Suárez et al 2016), bobcats (Lynx rufus; Riley et al 2007;Serieys et al 2013), stoats (Mustela erminea) and weasels (Mustela nivalis; McDonald et al 1998;Elmeros et al 2011), red foxes (Vulpes vulpes; Tosh et al 2011;Tjus 2014), polecats (Mustela putorius; Shore et al 2003), and stone martens (Martes foina; Elmeros et al 2018). In Norway SGARs have been detected in raptors found dead in the wild, such as the golden eagle (Aquila chrysaetos) and eagle owl (Bubo bubo; Langford et al 2013).…”

Current status of American mink Neovison vison in Great Britain: a review of the evidence for a population decline

“…Anticoagulant rodenticide residues were detected in 79% of 68 road‐kill polecat carcasses tested, and the rate of detection since the 1990s had almost doubled in line with a moderate nationwide increase in anticoagulant rodenticide usage (Sainsbury et al ). Similarly, 79% of 99 mink trapped in Scotland had detectable residues of at least one anticoagulant rodenticide, and over 50% of positive animals had residues of two or more (Ruiz Suárez et al ). Exposure rate was 1.7 times higher for mink caught in areas with a high density of farms than for those in low‐density farming areas.…”

First evidence of anticoagulant rodenticides in fish and suspended particulate matter: spatial and temporal distribution in German freshwater aquatic systems

“…It is thus not surprising that residues of anticoagulant rodenticides, especially of the second-generation compounds, have been detected in a large variety of species. Residues of rodenticides were detected for example, in barn owls (Geduhn et al 2016 , Newton et al 1990 ), tawny owls (Walker et al 2008 ), common buzzards (Berny et al 1997 ), golden eagles (Langford et al 2013 ), polecats/mink (Elmeros et al 2018 , Fournier-Chambrillon et al 2004 , Ruiz-Suarez et al 2014 , 2016 , Shore et al 2003 ), weasels (McDonald et al 1998 ), stoats (Elmeros et al 2011 ), foxes (Berny et al 1997 , Geduhn et al 2015 , McMillin et al 2008 , Tosh et al 2011 ), hedgehogs (Dowding et al 2010 ), and snails (Alomar et al 2018 ).…”