Publication Date:
2022-05-25
Description:
Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 147 (2008): 331-338, doi:10.1016/j.cbpc.2007.12.003.
Description:
Many laboratory studies have documented that mercury can be toxic to fish, but it is
largely unknown if mercury is toxic to fish in their natural environments. The objective of our
study was to investigate the toxic effects of mercury on northern pike (Esox lucius) at Isle
Royale, Michigan. In 124 northern pike from eight inland lakes, concentrations of total mercury
in skin-on fillets ranged from 0.069 to 0.622 µg/g wet wt. Concentrations of total mercury in
livers increased exponentially compared with concentrations in fillets, to a maximum of 3.1 µg/g
wet wt. Methylmercury constituted a majority of the mercury in livers with total mercury
concentrations 〈0.5 µg/g wet wt, but declined to 28-51% of the mercury in livers with total
mercury concentrations 〉0.5 µg/g wet wt. Liver color (absorbance at 400 nm) varied among
northern pike and was positively related to liver total mercury concentration. The pigment
causing variation in liver color was identified as lipofuscin, which results from lipid peroxidation
of membranous organelles. An analysis of covariance revealed lipofuscin accumulation was
primarily associated with mercury exposure, and this association obscured any normal
accumulation from aging. We also documented decreased lipid reserves in livers and poor
condition factors of northern pike with high liver total mercury concentrations. Our results
suggest (i) northern pike at Isle Royale are experiencing toxicity at concentrations of total
mercury common for northern pike and other piscivorous fish elsewhere in North America and
(ii) liver color may be useful for indicating mercury exposure and effects in northern pike at Isle
Royale and possibly other aquatic ecosystems and other fish species.
Description:
Financial support was provided by the U.S. Environmental Protection Agency STAR Graduate Fellowship Program to P.E.D.
Keywords:
Mercury
;
Methylmercury
;
Northern pike
;
Liver
;
Lipofuscin
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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