Physiological and Behavioural Aspects of Swimming in Sturgeon

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Migration, reproduction, and predator-prey interactions depend heavily on a fish's ability to swim. Swimming efficiency and performance is related to a species' physiology, morphology and behaviour, and the environmental challenges the animal faces (e.g., temperature changes, velocity changes). The focus of my research program is to understand the influence of various abiotic and biotic factors on the swimming capacity and energetics of the sturgeon, a "primitive fish." The rationales for utilizing the sturgeon as a model are many-fold, including: (i) biological, because of its intermediate evolutionary position between sharks and teleosts; (2) their excellent capacity to deal with acute and chronic stressors; (3) commercial, owing to their highly-prized meat and caviar; (4) conservation, as many populations of sturgeon are considered to be critically endangered due to overharvesting and habitat degradation/encroachment. Our recent findings show that sturgeon possess unique morphological and behavioural attributes that affect their swimming patterns (e.g., station-holding) and performance (e.g., length of time swimming). My long-term objective is to address the interplay of behaviour, morphology and physiology on the metabolic costs of swimming in sturgeon. The short-term goals here focus on the costs of transport, swimming efficiency, and metabolic fuel use patterns (i.e., whether they use carbohydrates, lipids or proteins) at different speeds and temperatures in shortnose sturgeon. In addition, I will examine the metabolic costs of repeat swimming challenges and the importance of light levels on swimming performance in sturgeon. The proposed experiments, using swim flume technology, are designed to test novel hypotheses with regard to metabolic costs associated with swimming in a primitive fish. My research program is original in that many swimming studies focus on high-performance species, such as salmon and trout. In contrast, sturgeons are slow-moving, bottom-feeding fishes, but more information is needed to better understand the factors that affect swimming in these primitive fishes. Such knowledge would provide invaluable insight into how locomotion evolved in vertebrates. In the global sense, my research has both basic (e.g., exercise physiology) and applied (e.g., global warming issues, migration costs, stocking strategies) importance. Obstacles to migration, such as dams and water diversions, can block or impede sturgeon migration and reproduction. Such obstacles, combined with climate change, can also affect water temperatures and flows. Thus, my work will help to define the physiological limits of these ancient fish in response to human activities and global climate change.