John Wiley & Sons, Ltd.

Using molecular biomarkers and traditional morphometric measurements to assess the health of slimy sculpin (Cottus cognatus) from streams with elevated selenium in north‐eastern British Columbia

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Canadian fish‐based environmental effects monitoring programs use individual and population level endpoints to assess aquatic health. Impacts of coal mining and selenium (Se) exposure were assessed in slimy sculpin (Cottus cognatus) from reference streams located both inside and outside of a coal zone, and from one stream with a history of coal mining, using traditional environmental effects monitoring endpoints. In addition, physical characteristics of the streams and benthic macro‐invertebrate communities were assessed. To determine if the assessment of effects could be improved by including molecular markers, real‐time PCR assays were optimized for genes associated with reproduction (vtg, esr1, star, cyp19a1, and gys2), and oxidative and cellular stress (sod1, gpx, gsr, cat, and hsp 90). Water Se levels exceeded guidelines in the stream with historical mining (4 µg/L), but benthic macro‐invertebrates did not exceed dietary thresholds (2 ‐ 3 µg/g dw). Whole‐body Se levels were above British Columbia's tissue guideline in fish from all streams, but only above the draft USEPA criterion (7.91 µg/g dw) at the reference stream inside the coal zone. Some markers of cellular and oxidative stress were elevated in fish liver at the exposed site (sod1, gpx), but some were lower (cat, sod1, gpx, gsr, hsp90) in the gonad of fish inside the coal zone. Some of the differences in gene expression levels between the reference and impacted sites were sex‐dependent. Based on benthic macro‐invertebrate assessments, we hypothesize that traditional and molecular differences in slimy sculpin at impacted sites may be driven by food availability, rather than Se exposure. This is the first study to adapt molecular endpoints in the slimy sculpin for aquatic health assessments. This article is protected by copyright. All rights reserved

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