Potential of invasive alien top predator as a biomonitor of nickel deposition – the case of American mink in Iceland

Figures & data

Figure 1. Sampling sites (black dots) of American mink in the Brokey archipelago, Breiðafjörður Bay, West Iceland

Table I. Concentrations of nickel (ppm) in the spleens of Neovison vison in Breiðafjörður Bay, West Iceland

		Ni (ppm)
All animals (n = 65)	Mean ± SD	0.134 ± 0.2954
	Median	0.067
	CV	220.71
	Range	(0.026–2.305)
Females (n = 30)	Mean ± SD	0.124 ± 0.1624
	Median	0.068
	CV	130.99
	Range	(0.026–0.890)
Males (n = 35)	Mean ± SD	0.142 ± 0.3742
	Median	0.064
	CV	263.44
	Range	(0.030–2.305)

CV: coefficient of variation; SD: standard deviation.

Figure 2. Comparison between male and female mink in terms of (a) nickel concentration in the spleen (ppm), (b) spleen weight (g), (c) tailless body length (cm) and (d) body weight (g)

Table II. Correlation coefficient between nickel concentration in the spleen and morphometric traits of all captured mink

		Ni (ppm)	Weight g
All animals (n = 65)	Spleen weight (g)	−0.16	0.36*
	Body length without tail (cm)	−0.12	0.82*
	Body weight (g)	−0.05	-
Females (n = 30)	Spleen weight (g)	−0.11	0.70*
	Body length without tail (cm)	−0.18	−0.11
	Body weight (g)	−0.07	-
Males (n = 35)	Spleen weight (g)	−0.08	0.32*
	Body length without tail (cm)	−0.04	0.63*
	Body weight (g)	−0.02	-

*Statistically significant at p < 0.05.

Figure 3. Spatial distribution of nickel content in American minks’ spleen in Breiðafjörður Bay, West Iceland

Table III. A list of conditions for an “ideal” biomonitor and the corresponding features of American mink in Iceland [Stefánsson et al., 2016; Dunstone, 1993; Tataruch and Kierdorf, 2003; Ellenberg, 1991; Rosenberg and Resh, 1993; Hilty and Merenlender, 2000; Füreder and Reynolds, 2003]

Feature	American mink
Taxonomic soundness	Species easily recognisable by non-specialists, as there is no possibility of confusion with any indigenous species
Spatial representativeness	Large population, widely distributed across the country
Availability and practicability of specimen collection	Game species systematically hunted in terms of population control; total eradication highly unlikely
Experimental suitability	Species has been used in laboratory experiments; sentinels for human health risks, high ability for quantification and standardisation
Low mobility (local indication)	Territorial species (although periodically very mobile)
Ecological representativeness	Well-known ecological as well as physio-morphological and behavioural characteristics; top predator; relatively easily identifiable feeding habits; semi-aquatic species
Sensitivity to environmental stressor	Relatively well-known ecotoxicological conditions; tolerant to the pollutant under study and directly indicating xenobiotic level by its accumulated concentration in organs
Reproducibility of specimen collection	Widely distributed non-indigenous, invasive population around the world
Public attitude	Socially acceptable hunting harvest
Economic profitability	State-supported bounty system for culling, availability of whole carcasses offering the ability to analyse all organs and tissues; possibility to exclude the exploitation of native species for biological monitoring purposes, while maintaining control of the harmful invasive alien species

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