Pattern and process in global change biology: from physiology to fisheries sustainability

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A fundamental question in population ecology is what factors influence variation in the intrinsic rate of population increase and intrinsic sensitivity to extinction among species? My vision is to arrive on a remote island armed only with the tools of an 18th century naturalist (and a computer and the models I develop from this NSERC DG) to undertake ecological risk assessments of the local fisheries. Using only a thermometer, field guide, dissection kit, and light microscope, I wish to rank the local fish fauna using proxies for their maximum population growth rate, flagging species warranting protection and others that can be fished sustainably. Specifically, the long-term goal of my research program is to assess ecological risk of a vast number of species using principles that directly relate their physiology to their fisheries sustainability. Over the past two decades, I have made significant progress in understanding the physiological basis of the response of species and assemblages to climate change. I now wish to predict maximum population growth rates and fisheries sustainability from the interplay of physiology, lifestyle and abiotic environment upon life histories and demography. I will bridge three currently unconnected, but related, theories to develop a physiological theory of demography and fisheries sustainability: (1) the size-dependence of metabolic rate, (2) Pauly’s gill area theory of growth, and (3) Charnov’s life history invariants. My goal will be realized through five interrelated short-term objectives, to determine how: (1) gills and hearts influence the size-dependency of metabolic rate [MSc 1], (2) gills and hearts influence the somatic growth trajectory [PhD 2], (3) growth fixes life histories and maximum population growth rate [PhD 3], (4) environment shapes the geography of life histories and population dynamics [PhD 4], (5) environmental physiology of life histories predict extinction risk and fishing mortality (PhD 5). My proposal integrates classical morphological physiology with fundamental life history theory to develop predictive models of the spatial patterning of extinction risk and fishing mortality - the principle threatening process. This will be done by field sampling, and laboratory estimation of gill area and heart mass for those teleost and elasmobranch fishes for which we have metabolic rate, growth and other life history data. I will then used advanced statistical modeling techniques to map the global distribution of life histories and maximum population growth based on environmental links to somatic growth. These datasets and methods will then allow me to model the potential risk of extinction and global fishing mortality based on life histories and observed extinction risk. Impact of proposed research: The proposed program of work is highly novel in that I seek to understand the physiology of fisheries sustainability by developing global models of extinction risk and fishing mortality founded upon the environmental and physiological basis for growth, and in turn relationship between growth to life histories and population dynamics. This work has direct applied impact in three ways, by enabling: (i) estimation of metabolic rate from gill areas (without the need for complex, time consuming experimental work), (ii) estimation of maximum population growth rate from morphometrics (gill area and maximum size), and (iii) modeling ocean-wide maps of relative extinction risk and fishing mortality. Never before has Canada needed evidence-based policy making. My work will continue to have significant benefits to Canada in that 5 graduate and 10 undergraduate HQP trained the science and communication of global change.