Archives of Environmental Contamination and Toxicology (2018) 75:111–120
Mercury Concentrations in Double‑Crested Cormorant Chicks Across
Raphael A. Lavoie
· Linda M. Campbell
Received: 13 December 2017 / Accepted: 2 May 2018 / Published online: 10 May 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2018
Mercury (Hg) biomagniﬁes in aquatic food chains and can reach high concentrations in ﬁsh–eating birds. Spatial patterns
of Hg have been found in freshwater ecosystems across Canada for many taxa, including ﬁsh and birds. However, it often is
challenging to sample a representative population size of adult birds to monitor concentrations of contaminants over a large
spatial scale. Moreover, adult birds can migrate and can show a contaminant proﬁle that may not be representative of local
resources. The goals of this study were (1) to determine if there was a spatial pattern of Hg concentrations in piscivorous
birds, (2) to develop a model to estimate Hg concentrations in breeding adults using chicks as proxy, and (3) to develop pre-
dictive equations among non-lethal tissues that are representative of local resources in adults (blood and growing feathers).
Double-crested Cormorant (Phalacrocorax auritus) chick growing feathers were sampled at 19 sites across Canada. Adult
tissues (freshly grown feathers and blood) were sampled at ﬁve of those locations to establish correlations between age classes
and between adult tissues. We found an increase in Hg concentrations with latitude up to 50°N followed by a decrease. There
was a decrease in Hg concentrations from west to east, which contradicts previous studies. We found a good correlation of
Hg concentrations between adults and chicks and among adult tissues. Our study shows that chicks are representative of
adults and can be a suitable proxy for monitoring local mercury concentrations across Canada.
Mercury (Hg) biomagniﬁes in aquatic food chains (Lavoie
et al. 2013) and can reach toxic concentrations in upper-
trophic-level organisms such as ﬁsh–eating birds (Ackerman
et al. 2016b; Depew et al. 2012; Jackson et al. 2016; Wolfe
et al. 1998). Hg is ubiquitous, but concentrations in wild-
life vary spatially depending on the physicochemistry of the
waterbody (e.g., pH) and Hg input in the system (e.g., atmos-
pheric deposition and point sources; Clayden et al. 2013;
Kidd et al. 2012). The trophic structure of a system will also
deﬁne Hg concentrations in apex predators due to spatial
variations in trophic levels (e.g., food chain length; Kidd
et al. 2012; Lavoie et al. 2013; Vander Zanden and Fetzer
2007). Spatial patterns of Hg have been found in freshwater
ecosystems across North America for many taxa, including
ﬁsh and bird species and concentrations typically increase
towards southeastern Canada and northeastern United States
(Depew et al. 2013; Evers et al. 1998, 2003; Wente 2004).
These patterns are best explained by high deposition of Hg
and sulfate, low pH, and surrounding landscapes dominated
by forests and/or wetlands (Depew et al. 2013; Driscoll et al.
2007; Evers et al. 2007).
Selecting a representative species to monitor concentra-
tions of Hg over a large spatial scale represents a challenge.
Characteristics for good aquatic monitoring species require
that they are widespread, abundant, easy to access, easy
to capture (and recapture where repeated measurements
are necessary), have high territorial ﬁdelity, are high in
the food chain (e.g., piscivorous), and have a long lifespan
(Evers et al. 1998). Low cost is also an asset in the choice of
species used by monitoring agencies. The Double-crested
Cormorant (Phalacrocorax auritus), an upper-trophic-level
piscivorous bird, meets these requirements when nesting
on the ground (Dorr et al. 2014; Lavoie et al. 2014; 2015).
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s0024 4-018-0533-y) contains
supplementary material, which is available to authorized users.
* Raphael A. Lavoie
Biology Department, Queen’s University, 116 Barrie St.,
Kingston, ON K7L 3N6, Canada
Present Address: Département de Sciences Biologiques,
Université de Montréal, Pavillon Marie-Victorin CP6128,
Succ. Centre-Ville, Montreal, QC H3C 3J7, Canada
Environmental Science, Saint Mary’s University, 923 Robie
Street, Halifax, NS B3H 3C3, Canada