Effects of chronic, sublethal ferric iron exposure on the critical swim speed of rainbow trout (Oncorhynchus mykiss) and critical thermal maximum of cutthroat trout (Oncorhynchus clarkii)
Date
2015
Authors
B'ey, Theadora Danita, author
Ramsdell, Howard, advisor
Legare, Marie, committee member
Spraker, Terry, committee member
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Abstract
Two experiments were performed to aid in establishing a new Colorado chronic water quality criterion for total iron. Although the effects of dissolved ferrous iron have been well documented, limited data are available regarding ferric iron specific toxicity in aquatic ecosystems. Juvenile rainbow trout (Oncorhynchus mykiss) critical swim speed (Ucrit) was measured to establish if there was a relationship between chronic sublethal ferric iron exposure and changes in Ucrit. The gills were examined for histological changes and fish growth was measured as endpoints. No significant changes in Ucrit growth or gill histology were found in the first experiment, although suggestive trends were noted. The Ucrit experiment was challenging on multiple levels, in part due to the diminutive size of the fish used in the experiment. A second study was performed on juvenile cutthroat trout chronically exposed to sublethal concentrations of ferric iron. The critical thermal maximum (CTmax) and changes in weight were tested. There were no significant changes in CTmax or weight measured in the second experiment.