Aaron Fisk

Dr. Aaron Fisk
Canada Research Chair in Trophic Ecology

All animals must eat. The availability of edible food, however, is profoundly influenced by nature’s rhythms pressing up against increasing consumptive demands and man’s impact on the environment.

All animals, including humans, are embedded in food webs. An organism’s position within a food web is central in determining the amount of energy and nutrients available to it. Strategic positioning is key to survival. Global change can profoundly alter the structure and links within food webs, ultimately changing the types and abundance of organisms able to survive in an ecosystem. Our ability to sustain healthy ecosystems and feed burgeoning populations depends on understanding how nature and humans interact with the structure and function of ecosystems.

Dr. Fisk’s research will simultaneously examine the structure, function and flow of nutrients in aquatic food webs, using a suite of naturally-occurring and anthropogenically-introduced chemical tracers. In controlled laboratory studies he will calibrate the tracers for aquatic organisms (e.g., walleye) and in detailed field studies he will apply study results to questions on the structure and function of aquatic ecosystems. These tracers are also important for the health of humans and wildlife. The right combination of essential fatty acids, for example, promotes human health and fish growth, but often results in simultaneous exposure to toxic mercury and PCBs.

Characterizing and understanding the influence of natural variation and anthropogenic stress on food webs is essential for effective conservation and management and ultimately for healthy and sustainable ecosystems. Dr. Fisk’s research will develop tools for studying ecosystem structure and provide new information on how ecosystems function and how they react to environmental stressors.