Determination of selenium in fish from designated critical habitat in the Gunnison River, Colorado, March through October, 2012

This report presents results for the summer 2012 sam-pling of muscle plugs from common carp (Cyprinus carpio), bonytail chub (Gila elegans), Colorado pikeminnow (Ptycho-cheilus lucius), and razorback suckers (Xyrauchen texanus) inhabiting critical habitat in the Gunnison River in western Colorado. Total selenium in fish muscle plugs was determinedby instrumental neutron activation analysis. Total selenium concentrations (range and mean ± standard deviation) in micrograms per gram dry weight were 6.0 to 10.7, 8.8 ± 1.3 for common carp; 2.9 to 8.7, 5.6 ± 2.4 for Colorado pikemin-now; and 1.4 to 7.3, 3.4 ± 2.7 for razorback sucker. The selenium concentration for one bonytail chub sample was 0.8 micrograms per gram dry weight. Selenium concentrations in muscle plugs from 1 Colorado pikeminnow and 12 common carp exceeded the 8 micrograms per gram dry weight toxicity guideline for selenium in fish muscle tissue.