Hello everyone! My name is Ellie Prow and I’m from Onaway, Michigan. I am going into my senior year at Lake Superior State University (LSSU) pursuing a B.S. in Fisheries and Wildlife Management with a concentration of Conservation Officer, and a minor in Natural Resources Technology. Growing up close to Lake Huron made me excited early on to learn more about the Great Lakes and what goes on within them!
Ellie and Gwen Phillips sampling for larval fish in Lake Superior. Photo: Elliana Prow
This summer I am working at LSSU’s Center for Freshwater Research and Education (CFRE) as an aquatic food web research technician. Some main creatures of study are larval coregonine fish (e.g., lake whitefish and cisco) and zooplankton (what these larval fish eat).
A larval fish under the microscope. Photo: Elliana Prow
Lake whitefish abundances have been declining in some areas of the Great Lakes, and for us to further understand why they are declining, we are studying their larval stage and food resources available. In Lakes Michigan and Huron, invasive zebra and quagga mussels have decreased phytoplankton and subsequently zooplankton abundances. Since zooplankton have decreased in these lakes, less food may exist for larval fish, which can affect their growth and survival to older stages. However, more data are needed that characterize zooplankton dynamics and changes over time in shallow water beach (≤1 m depth) and nearshore (1-10 m depth) habitats, which serve as nursery habitat for larval fish. Lake whitefish larvae hatch in the spring around ice-off and are often found in shallow waters.
A variety of diet items from a larval fish. Photo: Elliana Prow
Further, zooplankton and larval fish can exhibit daily migration, resulting in differences depending on the time of day when one samples. Therefore, determining day versus night zooplankton community estimates in shallow water habitats could be important to understanding larval coregonine abundances. Through an Upper Great Lakes collaboration that includes twelve agencies, we sampled for zooplankton, larval coregonines, and other environmental variables on the beach and nearshore and at day and night at many locations in 2023 and again in 2024.
Across teams, our study sites included Grand Marais to Sault Ste. Marie in eastern Lake Superior; the Apostle Islands in western Lake Superior; Green Bay to the Straits of Mackinac in Lake Michigan; and Saginaw Bay, north to the Straits of Mackinac, and then east to Detour in Lake Huron. LSSU sampled closely with Bay Mills Indian Community and Sault Ste. Marie Tribe of Chippewa Indians to sample sites spanning Lakes Superior, Michigan, and Huron. Sampling started at ice-off and each site was sampled three times approximately every two weeks at day and at night. A subset of those beach sites had paired nearshore samples from the boat at day and at night. Zooplankton were collected with a plankton net with horizontal hand tows. Larval fish were collected using neuston nets pulled horizontally in the water column. Many other environmental data were also collected such as water temperature, dissolved oxygen concentration, pH, specific conductivity, chlorophyll a, and substrate and shoreline conditions.
Ellie sampling at night. Photo: Elliana Prow
After we collected samples, they were brought to the lab for processing. Under the microscope, we identified and counted the fish. We are quantifying the zooplankton samples and processing the diets of the fish, to count and measure what they are eating, and how their diet may relate to ambient water column food conditions.
Ellie (left) and Gwen (right) analyzing a laval fish diet under the microscope. Photo: Elliana Prow
Through the MI Sea Grant internship, and this summer position, I had two amazing opportunities to give a poster presentation at conferences. The first conference I attended was the Michigan chapter of the American Fisheries Society (AFS). This conference was in Lansing, MI, and was a three-day conference. I listened and learned about a lot of research going on all around Michigan and the Midwest, and this was my first experience presenting my research. The second conference I attended was the international Association for the Sciences of Limnology and Oceanography (ASLO) conference in Madison, WI. This conference was five days and researchers from around the world came to present their research. I also presented my research as a poster at ASLO, which was a great experience getting to talk to many researchers with different backgrounds to get new ideas and knowledge. I met a lot of new people and made many new connections at these conferences.
Elliana’s poster presentation at ASLO. Photo: Elliana Prow
Group photo at the ASLO conference in Madison, with the capitol building in the background (from left to right- Ellie, Gwen, Jon, Dexter). Photo: Elliana Prow
Understanding how zooplankton communities differ at day versus night and from the beach versus nearshore in the Great Lakes, and their relations to larval fish is important. This research has provided me with so much experience from collecting data, processing data, analyzing data in R, making connections with people, and presenting on results. My favorite part of this research was going out and collecting data even with the early mornings and late nights. I look forward to gaining more experience presenting with Michigan Sea Grant in August and learning from and meeting others there!
[Editor’s note: Elliana delivered an excellent presentation at the 2024 intern symposium. A recording of the symposium can be found here.]
Sunset at Grand Marais, Lake Superior. Photo: Elliana Prow
