Reference number : GC-2017-Q1-02309, amendment number : , agreement type : G, recipient legal name : Trites, Andrew (The University of British Columbia), recipient country : CA, recipient province : nan, recipient city : British Columbia|Colombie-Britannique, recipient postal code : nan, program name english : Discovery Grants Program - Individual, program name french : Programme de subventions à la découverte - individuelles, program purpose english : A nutritional consequence of the co-evolution between marine mammals and their prey appears to be that some potential prey species are no longer energy-rich enough to support the energetic needs of some species of marine mammals, while other marine mammals with lower energy requirements did not evolve high performing musculature, and have therefore adapted to survive on slower moving and generally lower quality prey. As such, fishing and ecosystem shifts that alter the relative abundances of high-energy and low-energy prey species can cause rapid changes in marine mammal numbers depending on which evolutionary pathway the marine mammals followed&mdash;even when high biomasses of potential prey species are present. This has been termed the &ldquo;junk food&rdquo; hypothesis. I propose to test the general applicability of the junk food hypothesis to marine mammals using bioenergetic models and regional time series of dietary information and population estimates. I will begin by comparing the food requirements of all marine mammals predicted by detailed bioenergetic models with those derived from generalized equations that scale consumption as a function of body mass. My expectation is that this will result in new generalized consumption equations for at least two categories of marine mammals separated by differences in the quality of prey they evolved to consume. I will also undertake a detailed spatial analysis of the population dynamics of marine mammals in the North Pacific relative to the 1975-1976 Oceanic Regime Shift when significant increases and decreases of fish and marine mammals occurred opposite to one another in the Gulf of Alaska and the California Current System. For the next 5 years, I will work with 4 graduate students and 5 undergraduates to formulate the models and build the necessary databases of abundances, distributions and diets for the intensively studied species of marine mammals, particularly in the North Pacific Ocean. I will also establish a complementary database on prey quantity, quality, composition, and distribution using data provided by PICES member countries (Japan, Korea, China, Russia, Canada and the United States). I expect the results to 1) establish trophic linkages and dependencies between marine mammals and their preferred prey species, 2) yield new generalized equations for estimating consumption by marine mammals, 3) test the applicability of the junk-food hypothesis as the major driver of marine mammal population dynamics, and 4) aid in predicting the spatial and temporal effects of climate change on consumption and distribution of marine mammals. The graduate students supported by this study will develop skills in programming, data analysis, and fisheries and marine mammal research; and will take part in international conferences, and in workshops and symposiums organized at PICES annual meetings to support this initiative., program purpose french : A nutritional consequence of the co-evolution between marine mammals and their prey appears to be that some potential prey species are no longer energy-rich enough to support the energetic needs of some species of marine mammals, while other marine mammals with lower energy requirements did not evolve high performing musculature, and have therefore adapted to survive on slower moving and generally lower quality prey. As such, fishing and ecosystem shifts that alter the relative abundances of high-energy and low-energy prey species can cause rapid changes in marine mammal numbers depending on which evolutionary pathway the marine mammals followed&mdash;even when high biomasses of potential prey species are present. This has been termed the &ldquo;junk food&rdquo; hypothesis. I propose to test the general applicability of the junk food hypothesis to marine mammals using bioenergetic models and regional time series of dietary information and population estimates. I will begin by comparing the food requirements of all marine mammals predicted by detailed bioenergetic models with those derived from generalized equations that scale consumption as a function of body mass. My expectation is that this will result in new generalized consumption equations for at least two categories of marine mammals separated by differences in the quality of prey they evolved to consume. I will also undertake a detailed spatial analysis of the population dynamics of marine mammals in the North Pacific relative to the 1975-1976 Oceanic Regime Shift when significant increases and decreases of fish and marine mammals occurred opposite to one another in the Gulf of Alaska and the California Current System. For the next 5 years, I will work with 4 graduate students and 5 undergraduates to formulate the models and build the necessary databases of abundances, distributions and diets for the intensively studied species of marine mammals, particularly in the North Pacific Ocean. I will also establish a complementary database on prey quantity, quality, composition, and distribution using data provided by PICES member countries (Japan, Korea, China, Russia, Canada and the United States). I expect the results to 1) establish trophic linkages and dependencies between marine mammals and their preferred prey species, 2) yield new generalized equations for estimating consumption by marine mammals, 3) test the applicability of the junk-food hypothesis as the major driver of marine mammal population dynamics, and 4) aid in predicting the spatial and temporal effects of climate change on consumption and distribution of marine mammals. The graduate students supported by this study will develop skills in programming, data analysis, and fisheries and marine mammal research; and will take part in international conferences, and in workshops and symposiums organized at PICES annual meetings to support this initiative., agreement title english : Evolutionary dependencies of marine mammals on their preferred prey species: a potential paradigm shift to guide fisheries management and conservation initiatives, agreement title french : Evolutionary dependencies of marine mammals on their preferred prey species: a potential paradigm shift to guide fisheries management and conservation initiatives, agreement number : RGPIN, agreement value : 140000.0, agreement start date : 2017-05-10, agreement end date : nan, description english : nan, description french : nan, expected results english : nan, expected results french : nan, additional information english : Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023), additional information french : Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023), owner organization : nserc-crsng, owner organization title : Natural Sciences and Engineering Research Council of Canada | Conseil de recherches en sciences naturelles et en génie du Canada