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Thesis Title: Understanding the ecological consequences of stress in wild fish using exogenous cortisol implants
Sarah is a M.Sc. candidate currently working with Dr. Steven Cooke in the lab of fish ecology and conservation physiology at Carleton University. Sarah’s undergraduate education gave her a thorough background in applied ecological theory and methods. Additional focus in fish behaviour, physiology and microbiology gave her important lab and field skills. The Cooke lab is the perfect place to integrate fish physiology and behaviour with ecological concepts.
Sarah has conducted research on two systems using two different fish species. The first organism studied was the bluegill sunfish (Lepomis macrochirus), a Centrarchid abundant in Eastern Ontario lakes. In this system, fish encounter many stressors throughout their lifetimes that have the potential to alter physiological systems and in turn, behaviour and fitness. Understanding how these stressors can affect fish condition and physiology can help us determine how their ecology is affected as well. This was done using exogenous cortisol (a stress hormone) implanted into wild bluegill sunfish. After receiving implants, fish were exposed to further ecologically relevant stressors and then monitored closely to determine how multiple stressors affected their condition and survival.
The second portion of Sarah’s research was conducted on Fraser River pink salmon (Oncorhynchus gorbuscha) on their spawning grounds at the Weaver Creek spawning channel. Upon entry to the spawning channel, fish were subjected to varying degrees of stress and then were placed back into the channel or were observed for changes in reproductive behaviour and success. Exogenous cortisol implants were used, as well as metyrapone, an endocrine blocker. This study is among the first to manipulate cortisol levels experimentally in the wild, while determining how stress affects reproductive success. It will aid in clarifying the role of cortisol during salmon migrations, especially its role on spawning grounds during pink salmon’s final maturation.
Background:
2007 - Honours B.Sc., Cornell University, Natural Resources with a concentration in Applied Ecology
Thesis Topic: A comparison of nearshore fish sampling gears in Oneida Lake, New York.
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