title: The efficacy of scale sampling for monitoring trace element concentrations and stable isotopes in commercially harvested walleye (Sander vitreus).
abstract: Commercial and sport fishes are subject to rigorous monitoring for concentrations of elements that could pose threats to human health, with numerous advisories issued by authorities annually for those fisheries with high mercury (Hg) concentrations. In Lake Winnipeg, Manitoba, Canada, the commercial walleye fishery is valued at more than $20 million/year, but has historically been subject to Hg advisories. We used an information theoretic approach to evaluate the utility of non-destructive fish-scale sampling to predict As, Mn and Hg concentrations, as well as stable isotope values in walleye muscle by analysing paired samples. Hg concentrations in scales were significantly related to those in muscle (r(2) = 0.75), but the relationships were weaker for As and Mn. The δ(15)N values in scales predicted δ(15)N in muscle reasonably well (r(2) = 0.72), whereas scale δ(13)C and δ(34)S had less predictive power for estimating their respective muscle stable isotope values. For all three isotope values, sex was a marginal predictor, with parameter confidence intervals bounding zero. Analytical constraints currently limit the utility of non-destructively analysing scales for Hg, but hindcasting trophic changes using archived walleye scales may be useful in understanding shifts in nutrients and production, particularly in impacted lake systems.
authors: a Toxicology Centre , University of Saskatchewan , Saskatoon , SK , Canada.
authors: Amy F A
authors: AF
authors: Ofukany
authors: Keith A
authors: KA
authors: Hobson
authors: Leonard I
authors: LI
authors: Wassenaar
authors: Alexander L
authors: AL
authors: Bond
mesh_terms: D000818:Animals; D049628:Body Size; D002247:Carbon Isotopes / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D008350:Manitoba; D008628:Mercury / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000032:analysis; D010471:Perches / Q000378:metabolism*; D012737:Sex Factors; D012741:Sexual Maturation; D013460:Sulfur Isotopes / Q000032:analysis; D014018:Tissue Distribution; D014131:Trace Elements / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D013460:Sulfur Isotopes; D014131:Trace Elements; D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Lake Winnipeg; arsenic; carbon-13; fish scales; isotope ecology; manganese; mercury; nitrogen-15; non-destructive analysis; sulphur-34