Dr. Brandon Gerig is cited as a senior author in two new published papers:
“Intraspecific variation in stable isotopes provides insight into adfluvial migrations and ecology of brook trout in Lake Superior tributaries.”
Abstract: Lake Superior is one of the five Laurentian Great Lakes and the largest lake in the world by surface area. Lake Superior and its surrounding watershed support a wide range of species, provide a wealth of ecosystem services, and support a robust economy, much of which is reliant on the health of the ecosystem. Though Lake Superior continues to lead the other Laurentian Great Lakes in condition and quality, it has also undergone significant changes including chemical pollution, invasive species, and harmful algal blooms (HABs). The lake is also sensitive to climate change, with rapidly warming water temperatures, significant nutrient input from extreme storm events, and changes to habitat and food web structure, among other impacts. Understanding the current conditions, trends, and emerging threats to Lake Superior from local to ecosystem scales allows us to better manage the lake now and prepare for the future
“Food web structure of the Lake Superior fish community in 2021–2022.”
Abstract: The trophic linkages and ecological requirements of the Lake Superior fish community have not been assessed on a whole lake scale in over a decade. Here, we investigated the trophic dynamics across multiple species and habitat zones of Lake Superior. From April to October of 2021 and 2022, a total of five piscivore, four planktivore, and six benthivore species were collected by region and length class during bottom-trawl, standard gillnet, commercial cisco gillnet, and recreational angler surveys. To assess trophic linkages, stomach contents were measured to estimate biomass consumed and a multivariate analysis was used to assess diet composition by species, length, and region. We found a high degree of interconnectedness in the Lake Superior food web, with Mysis as a critical diet item for most fishes. Native piscivore diets varied by region and with ontogeny. Lake charr were important habitat couplers in the lake, exhibiting a diverse diet and opportunistic foraging strategy. Conversely, Pacific salmon were more restricted in their foraging. Planktivores and benthivores primarily consumed Mysis, with less reliance on Diporeia compared to previous studies. Lake whitefish and cisco were the exception to this pattern, with broader bathymetric depth distributions represented in their diets. We found the food web to be supported by a predominantly native species assemblage, with redundancies at all trophic levels.
Dr. Gerig is an Assistant Professor at the University of Wisconsin-Milwaukee School of Freshwater Sciences. He is an applied ecologist whose research is broadly focused on freshwater fish and the food webs that support them. Prior to joining UWM, Gerig served as an ecologist for the National Park Service where he co-led the Great Rivers Cooperative Ecosystem Studies Unit headquartered at the University of Missouri. From 2017-2022 he served as an assistant professor at Northern Michigan University (promoted to associate in 2022) were he taught and conducted research in the Upper Great Lakes.