[MARMAM] New Articles: Mercury in pinnipeds

Elizabeth McHuron emchuron at ucsc.edu
Fri Aug 14 15:02:21 PDT 2015

Dear Colleagues,

We are pleased to announce the publication of two articles on mercury in
pinnipeds that will be published in an upcoming issue of Archives of
Environmental Contamination and Toxicology. The full text of both articles
can be found in the Online First section on the journal website (
http://link.springer.com/journal/244/onlineFirst/page/1). If you do not
have access to this journal, please email either Sarah (sarahpeterson23@
gmail.com) or myself (emchuron at ucsc.edu) if you would like a pdf of either

Peterson SP, McHuron EA, Kennedy SN, Ackerman JT, Rea LD, Castellini JM,
O'Hara TM, and Costa DP (2015) Evaluating hair as a predictor of blood
mercury: the influence of ontogentic phase and life history in pinnipeds.
Arch Environ Contam Toxicol DOI 10.1007/s00244-015-0174-3

Mercury (Hg) biomonitoring of pinnipeds increasingly utilizes nonlethally
collected tissues such as hair and blood. The relationship between total Hg
concentrations ([THg]) in these tissues is not well understood for marine
mammals, but it can be important for interpretation of tissue
concentrations with respect to ecotoxicology and biomonitoring. We examined
[THg] in blood and hair in multiple age classes of four pinniped species.
For each species, we used paired blood and hair samples to quantify the
ability of [THg] in hair to predict [THg] in blood at the time of sampling
and examined the influence of varying ontogenetic phases and life history
of the sampled animals. Overall, we found that the relationship between
[THg] in hair and blood was affected by factors including age class,
weaning status, growth, and the time difference between hair growth and
sample collection. Hair [THg] was moderately to strongly predictive of
current blood [THg] for adult female Steller sea lions (*Eumetopias jubatus*),
adult female California sea lions (*Zalophus californianus*), and adult
harbor seals (*Phoca vitulina*), whereas hair [THg] was poorly predictive
or not predictive (different times of year) of blood [THg] for adult
northern elephant seals (*Mirounga angustirostris*). Within species, except
for very young pups, hair [THg] was a weaker predictor of blood [THg] for
prereproductive animals than for adults likely due to growth, variability
in foraging behavior, and transitions between ontogenetic phases. Our
results indicate that the relationship between hair [THg] and blood [THg]
in pinnipeds is variable and that ontogenetic phase and life history should
be considered when interpreting [THg] in these tissues.

McHuron EA, Peterson SP, Ackerman JT, Melin SR, Harris JD, Costa DP (2015).
Effects of age, colony, and sex on mercury concentrations in California sea
lions. Arch Environ Contam Toxicol DOI 10.1007/s00244-015-0201-4.


We measured total mercury (THg) concentrations in California sea lions
californianus*) and examined how concentrations varied with age class,
colony, and sex. Because Hg exposure is primarily via diet, we used
nitrogen (*δ*15N) and carbon (*δ*13C) stable isotopes to determine if
intraspecific differences in THg concentrations could be explained by
feeding ecology. Blood and hair were collected from 21 adult females and 57
juveniles from three colonies in central and southern California (San
Nicolas, San Miguel, and Año Nuevo Islands). Total Hg concentrations ranged
from 0.01 to 0.31 μg g-1 wet weight (ww) in blood and 0.74 to 21.00 μg g-1 dry
weight (dw) in hair. Adult females had greater mean THg concentrations than
juveniles in blood (0.15 vs. 0.03 μg g-1ww) and hair (10.10 vs 3.25 μg g-1 dw).
Age class differences in THg concentrations did not appear to be driven by
trophic level or habitat type because there were no differences in *δ*15N
or *δ*13C values between adults and juveniles. Total Hg concentrations in
adult females were 54% (blood) and 24% (hair) greater in females from San
Miguel than San Nicolas Island, which may have been because sea lions from
the two islands foraged in different areas. For juveniles, we detected some
differences in THg concentrations with colony and sex, although these were
likely due to sampling effects and not ecological differences. Overall, THg
concentrations in California sea lions were within the range documented for
other marine mammals and were generally below toxicity benchmarks for
fish-eating wildlife.

Best Regards,

Liz McHuron and Sarah Peterson

Elizabeth McHuron, PhD Student
Ecology & Evolutionary Biology
Center for Ocean Health, Long Marine Lab
100 Shaffer Rd.
University of California
Santa Cruz, CA 95060
emchuron at ucsc.edu
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