Physiological and cellular responses to environmental stressors during the early life history stages of fishes.

点击翻译按钮获取中文摘要

Temperature and low oxygen conditions (hypoxia) are perhaps the most common environmental stressors encountered by fish. Because they affect many aspects of biology they can substantially influence overall success and performance. In many instances, fish have evolved to cope with natural fluctuations in temperature and oxygen levels. However, global climate change and increased agriculture have resulted in rising water temperatures and eutrophication; these in turn have increased the frequency and magnitude of fluctuations in these stressors which pose a significant threat to fish populations. As a temperature sensitive, cold-water fish whose embryos develop in near freezing water, lake whitefish are an ideal species to study the effects of climate change and thermal pollution on fish. Moreover, lake whitefish are economically important and culturally significant to Canada's Indigenous peoples. This research program will increase our understanding of how environmental stressors affect fish in critical and sensitive early life stages from fertilization to the end of the first year of life. The goal is an understanding of how stressors interact and alter biology at the cellular, physiological and whole animal levels as fish cope, acclimatize and adapt to changing environments. The short-term goals of the research are: (1) Determine the extent to which exposure to stressors in the parental and embryonic stages alter temperature and hypoxia tolerance in embryos and fish in their first year of life with emphasis on the early critical stages; (2) Provide a better understanding of how environmental stress changes metabolism at the cellular (carbohydrates and lipids) and whole animal (oxygen uptake, transport and consumption) levels during early life stages. With this research we also aim to identify the short- and long-term impacts of this reprogramming and determine if they are beneficial or detrimental to overall performance; (3) Determine the roles of the cellular (heat shock and antioxidant) and physiological (i.e., cortisol via the hypothalamic-pituitary-interrenal pathway) stress responses in tolerating these stressors; (4) Characterize the development of the hypothalamic-pituitary-interrenal and -thyroid axes in lake whitefish and examine the effects that embryonic stressors might have on these axes which are important for normal embryo and post-hatch development. Over the course of this research program, my research team (5 graduate and 7 undergraduate students) and I will significantly enhance our understanding of how temperature and hypoxia stress interact and affect fish at multiple levels of biological organization. With a focus on thermally sensitive, cold-water fish populations from various lake types, data generated will help us better predict the short- and long-term impacts of climate change and agricultural activities on lake whitefish and the extent to which fish may cope, acclimatize and adapt to changing environments.