University of SaskatchewanHARVEST
  • Login
  • Submit Your Work
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      The effects of salinization on freshwater fishes of the Northern Great Plains

      Thumbnail
      View/Open
      HOOVER-DISSERTATION-2017.pdf (1.154Mb)
      Date
      2017-06-14
      Author
      Hoover, Zachary 1981-
      ORCID
      0000-0001-6305-264X
      Type
      Thesis
      Degree Level
      Doctoral
      Metadata
      Show full item record
      Abstract
      Salinization poses a threat to many inland aquatic ecosystems. Therefore, it is important to understand the potential implications of salinization on aquatic systems. Saline water bodies are prevalent in the Northern Great Plains of North America—an area that includes portions of Alberta, Saskatchewan, and several northern states in the United States. In this area, saline water bodies provide an environmentally important habitat for a variety of species. Salinization, both natural and anthropogenic, is predicted to increase in the Northern Great Plains in the future, but the potential effects on aquatic organisms remain largely unknown. To investigate these potential impacts, I first established lethal levels of salinity exposure in fathead minnows (Pimephales promelas), northern pike (Esox lucius), and walleye (Sander vitreus). This experiment also gave me a framework for determining relevant concentrations with which to test the effects of sub-lethal salinity exposure on fathead minnows. After deciding appropriate levels, I exposed minnows to one of three sub-lethal salinity concentrations crossed by one of three alarm cue concentrations—an indicator of imminent predation risk. I found that salinity reduced the overall intensity of antipredator behaviour in the highest salinity concentration, and also eliminated threat-sensitive responses at the intermediate salinity concentration. I then tested the effects of salinity on reproductive endpoints, both egg-based and behavioural, in fathead minnows. I found impacts on egg-based endpoints at all salinity levels, even the relatively low 1000 parts per million (ppm) concentration. I also found significant reproductive behaviour modification in the highest salinity treatment. I was then interested in determining an adequate acclimation point at which reproductive endpoints of minnows held in saline water matched those of minnows held in dechlorinated tap water. My data suggest that the acclimation point is approximately 14 weeks in 1000 ppm salinity, though it should be noted that my scope of inference may be limited by small sample sizes. Finally, I investigated second generation effects of minnows spawned, hatched, and reared in low-level salinity. I found no effect of salinity on morphology or antipredator responses.
      Degree
      Doctor of Philosophy (Ph.D.)
      Department
      Biology
      Program
      Biology
      Supervisor
      Chivers, Douglas P; Ferrari, Maud CO
      Committee
      Niyogi, Som; Pollock, Michael S; Janz, David M; Wei, Yangdou
      Copyright Date
      October 2017
      URI
      http://hdl.handle.net/10388/7915
      Subject
      fish
      salinity
      salinization
      Northern Great Plains
      fathead minnow
      sub-lethal
      antipredator
      reproduction
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      The University of Saskatchewan's main campus is situated on Treaty 6 Territory and the Homeland of the Métis.

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy