title: Comparing mercury concentrations across a thirty year time span in anadromous and non-anadromous Arctic charr from Labrador, Canada.
abstract: Anadromous and non-anadromous Arctic charr (Salvelinus alpinus) from multiple sample sites in Labrador, Canada were used to investigate possible differences in total mercury concentration ([THg]) between 1977-78 and 2007-09. The mean [THg] of anadromous Arctic charr was 0.03 μg/g wet weight (ww) in 1977-78 and 0.04 μg/g ww in 2007-09, while mean concentrations in non-anadromous conspecifics were 0.18 μg/g ww in 1977-78 and 0.14 μg/g ww in 2007-09. After correcting for the effects of fish age and fork-length, there was no widespread difference in the mean [THg] of anadromous or non-anadromous fish between the two time periods. However, at individual sites sampled during both time periods, [THg] increased, decreased, or did not change. The mean age of sampled fish declined from 9.0 years in 1977-78 to 8.2 years in 2007-09 for anadromous fish, and from 11.7 years to 10.5 years in non-anadromous Arctic charr. Similarly, mean fork-lengths decreased from 450 mm to 417 mm in anadromous and from 402 mm to 335 mm in non-anadromous fish between 1977-78 and 2007-09. The mean annual temperature at four Labrador weather stations increased by 1.6°C to 2.9°C between the two sampling periods. The lack of an overall trend in anadromous or non-anadromous Arctic charr [THg] despite warming temperatures that favour increased mercury methylation suggests that regional changes in climate-driven factors have had limited impacts on mercury exposure in Labrador freshwater or marine fish.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. Electronic address: sdorn@uwaterloo.ca.
authors.forename: S
authors.initials: S
authors.lastname: van der Velden
authors.affiliation: Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, A1C 5X1, Canada.
authors.forename: J B
authors.initials: JB
authors.lastname: Dempson
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Power
mesh_terms: D000818:Animals; D002170:Canada; D004784:Environmental Monitoring; D008628:Mercury / Q000378:metabolism*; D009523:Newfoundland and Labrador; D014337:Trout / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Anadromous; Arctic charr; Climate change; Lacustrine; Mercury; Temporal comparison