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Duluth, MN, United States

Trebitz A.,U.S. Environmental Protection Agency | Shepard G.,EMR Inc. | Brady V.,University of Minnesota | Schmude K.,University of Wisconsin-Superior
Journal of Great Lakes Research | Year: 2015

The European-origin faucet snail (Bithynia tentaculata) has been present in the lower Laurentian Great Lakes since the late 1800s but only very recently reached Lake Superior. Surveys from 2011 through 2013 found faucet snails abundant and wide-spread in the St. Louis River Estuary (reinforcing the estuary's status as non-native species introduction hotspot), with scattered finds elsewhere along Lake Superior's southern shore. Faucet snails were found primarily in littoral areas that had been sampled with D-frame nets. We discuss what is known of the distribution and timeline of the faucet snail in Lake Superior, and summarize morphological features helpful in distinguishing the faucet snail from other gastropods (e.g., the operculum). Given its potential for spread and impacts (including as waterfowl disease vector), the faucet snail warrants an elevated profile in non-native species monitoring, education, and decontamination measures in the upper Great Lakes. © 2015.

Erickson R.J.,U.S. Environmental Protection Agency | Mount D.R.,U.S. Environmental Protection Agency | Highland T.L.,U.S. Environmental Protection Agency | Hockett J.R.,U.S. Environmental Protection Agency | And 6 more authors.
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2010

The effects of diet-borne copper, cadmium, lead, and arsenic on juvenile fish were evaluated using a live diet consisting of the oligochaete Lumbriculus variegatus. In 30 d exposures, no effects were observed on the growth and survival of rainbow trout (Oncorhynchus mykiss), fathead minnow (Pimephales promelas), and channel catfish (Ictalurus punctatus) fed diets contaminated with copper [130-310 μg Cu (g dm) -1], cadmium [90-540 μg Cd (g dm) -1], and lead [850-1000 μg Pb (g dm) -1]. However, rainbow trout growth was reduced in a dose-dependent manner for diets contaminated with arsenic [26-77 μg As (g dm) -1]. These effects of arsenic on fish growth were accompanied by slower feeding rate, reduced food conversion efficiency, liver cell abnormalities, and fecal matter changes suggestive of digestive effects, and occurred to a similar extent whether the diet was exposed to arsenate or arsenite. Effects from these dietary levels of arsenic, and the absence of effects from these dietary levels of metals, were generally consistent with literature reports using laboratory diets amended with toxicant salts. These results also indicated that reported growth effects on rainbow trout fed diets of invertebrates collected from mining-contaminated areas of the Clark Fork River (Montana, USA) or exposed in the laboratory to Clark Fork River sediments are likely more attributable to the arsenic than the metals in those diets.

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