Great Lakes Fishery Commission

Species that connect heterogeneous habitats and thereby, spatial resources, have greater adaptive capacity to respond to environmental variation. Great Lakes food-webs consist of two communities; one in offshore waters and dominated by vertical migratory feeding strategies, and a second with depth restricted feeding strategies linked to nearshore production resources. Burbot are an important prey for lake charr and are known to undergo horizontal migration potentially linking the two food webs and serving to couple these habitats. Burbot have diverse spawning behaviors that likely protected them from extirpation by sea lampreys. In Lake Michigan, burbot demonstrate both nearshore-tributary and offshore spawning behaviors but it is unknown if this strategy occurs in Lake Superior. Burbot abundance in Lake Superior has declined concomitant with recovery of lake charr and remains suppressed due to strong predation pressure. As well, burbot are of increased importance due to a growth in recreational fishery interest. If Lake Superior burbot are supported solely by nearshore-tributary spawned fish, any increase in mortality from such an emergent fishery may have cascading implications for both burbot and lake charr. Here we propose to use mixed-methods to test the hypotheses that (1) genetic structure supports offshore spawning in Lake Superior, (2) burbot exhibit different natal origins and variable degrees of movement between nearshore and offshore habitats and (3) burbot couple nearshore and offshore energy channels, independent of spawning behavior. Resolving the contributions of spawned burbot in Lake Superior is critical for assessing population persistence, quantifying their importance in energy coupling as a lake charr prey resource, and has direct implications for evaluating; (1) connectivity among burbot populations, (2) sustainability of the burbot fishery, and (3) factors contributing to the rehabilitation, conservation and management of lake charr. \\r\\n\\r\\nFrom tributary, nearshore and offshore sampled burbot: 1) Determine the degree to which offshore sampled burbot are distinct from nearshore sampled conspecifics using genomics and otolith microchemistry; 2) Quantify energy coupling between the nearshore and offshore food-webs using stable isotopes and fatty acid ecological tracers; and 3) Contribute to the GLFC’s DEIC values to provide inclusive research experiences for students from u-STEM, fostering Great Lakes stewardship by training a more diverse generation of scientists. \\r\\n

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