The Effect of Municipal Wastewater Effluent on the Stress Response of Native Fish Species in the Bow River, Calgary, Alberta

Date
2017
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Abstract
Municipal wastewater effluent (MWWE) is a point-source of contamination to surface waters, and contains a mixture of nutrients and pharmaceuticals that are not completely eliminated during wastewater treatment processes. There have been many studies using reproductive endpoints to examine sub-lethal effects on fish sampled downstream from MWWE sources; however, few studies have examined effects on the stress performance of fish in the field, particularly in wild populations residing downstream from MWWE sources. The overall objective of this thesis was to determine whether exposure to MWWE in the field compromised the stress performance of native fish species in the Bow River, Calgary, Alberta. The hypothesis was that long-term exposure to MWWE would result in chronic stress and disruption of the hypothalamus-pituitary-interrenal (HPI) axis, leading to a reduced ability to respond to a secondary acute stressor and decreased energy stores due to enhanced energy demands. The results show that feral longnose dace (Rhinichthys cataractae; Chapter 2) and caged fathead minnows (Pimephales promelas; Chapter 3) sampled downstream from municipal wastewater treatment plants (WWTPs) in the Bow River, Calgary, Alberta, did not have elevated basal cortisol levels and were able to mount a cortisol response following exposure to an additional acute stressor. This suggests that there was no disruption in the HPI axis functioning. Furthermore, the energy stores in fish downstream from WWTPs were greater, which could be due to increased feeding, as fish were also greater in size. The effects detected on energy metabolism cannot be fully attributed to MWWE, as fish sampled from an upstream site also showed similar levels of glycogen stores as fish sampled from sites downstream from WWTPs. This suggests that stormwater and urban runoff may contribute to effects on the metabolism of fish.
Description
Keywords
Animal Physiology, Ecology
Citation
Lazaro-Côté, A. (2017). The Effect of Municipal Wastewater Effluent on the Stress Response of Native Fish Species in the Bow River, Calgary, Alberta (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28086