Supporting Cisco (Coregonus artedi) Restoration in Northeast Lake Michigan
Cisco (Coregonus artedi), also known as lake herring, was once among the most abundant native fish in Lake Michigan. Historically, cisco supported a large commercial fishery and was the primary prey for lake trout (Salvelinus namaycush) the main top predator in the system as well as providing a link between invertebrates and top piscivores. Due to intense settler overharvesting (regulated by the Department of Natural Resources), interactions with invasive species (primarily alewife, rainbow smelt, and sea lamprey) and habitat deterioration, populations plummeted in the early 1960s. A remnant population exists in northeastern Lake Michigan, with greatest abundance in Grand Traverse Bay. Since 2013, the population has shown signs of growth based on commercial catches and various fish surveys conducted in the lake. At the same time, a food web crisis is unfolding in the lake, caused by imbalance between Salmonines and forage fish. Forage biomass, mostly alewife and rainbow smelt, is at an all-time low as food web changes (especially the invasion of zebra and quagga mussels) have reduced available food resources to non-native planktivores. As result of this food shortage for prey fish, predator biomass in Lake Michigan is also declining. These conditions are more favorable for cisco and may be responsible for the signs of recovery of the remnant population. Thus, restoring cisco populations in Lake Michigan may now be possible and, if successful, would provide a management solution to the predator-prey imbalance. Consequently, there is current support for cisco restoration that would provide a more stable food base for top predators under the current food web structure. Nevertheless, the question of ecosystem carrying capacity has not yet been addressed.
Although there has been experimental stocking in Little Traverse Bay and efforts to enhance spawning habitat, managers have yet to decide on a restoration strategy. Managers have different views on how to proceed, ranging from allowing the existing populations to recover without intervention to stocking fingerlings from the same population or from populations from other lakes. To address this issue, the Lake Michigan Committee approved the formation of a Native Planktivore Task Group and charged the group with producing a white paper to guide restoration. The white paper draft identifies opportunities and risks of restoration alternatives. Nevertheless, there is a need to have an inclusive discussion on restoration among stakeholders of Lake Michigan fisheries to incorporate different perspectives.
- Goals & Objectives: This project has two main goals: i) to generate information on northeastern Lake Michigan ecosystem functional food web components to eventually implement a model that will guide cisco restoration, and ii) to investigate attitudes of Lake Michigan fishery stakeholders towards cisco restoration. These elements will provide tools to guide the decision making process to restore cisco in an ecological, social and cultural sound manner. The different elements of the project will address several essential questions such as what is the historical role of cisco for Michigan tribal fishing communities, how stakeholders of the current Lake Michigan fisheries perceive cisco restoration and what preferences are on the way restoration should be carried out. In particular, the project will focus on documenting and privileging the traditional knowledge of the Little Traverse Bay Bands of Odawa Indians and their desires as a sovereign indigenous nation. In regards to ecology elements the project will investigate cisco diets and diets of main cisco predators, cisco by-catch in Lake Michigan commercial and recreational fisheries, and cisco population abundance and age structure. These elements are necessary to implement an ecosystem food web model and evaluate the potential of the current food web to support a sustainable cisco population.
- Theoretical Justification, Social Benefit, or Significance: Findings of this project will improve understanding of Lake Michigan ecosystem dynamics and evaluate cisco removals by fisheries. Findings will also inform of social and cultural aspects related to cisco fisheries. The project will provide tools to guide management to restore cisco. A restored cisco population can provide for a more balanced ecosystem and for sustainable fisheries with substantial benefits to communities that depend on fishery ecosystem services.
- Specific Activities & Duration: To investigate stakeholder perspectives towards cisco restoration, the project will design and conduct surveys and interviews of recreational, commercial and tribal fishers, scientists and managers. To investigate fish diets, the project will include collecting and processing fish stomach samples for content analyses. The project will also include analysis of the data collected and other available data to estimate cisco and cisco predator consumption. To investigate the levels of by-catch on cisco populations, the project will consider surveying commercial fishing landings and recreational catch including catch of charter boat operations. To evaluate cisco population abundance and age structure, the project will include participation in ongoing hydroacoustic and seine surveys in Little Traverse Bay and data analysis. Analysis will consist on interpretation of hydroacoustic records and determination of cisco age based on otoliths. The scope of the proposed research will be scaled so the students have opportunities to gain experience in the difference aspects involved in the project but also that work can be completed during a 16-month project. It is envisioned that most of the field work will be conducted in spring-summer; processing of available stomach and fish samples will start during January; interpretation of hydroacoustic data will also start during January; data analysis will be completed within the next year and the draft and final report will be completed during the following 4 months.
- Integrative Approach: The proposed research will integrate skills of team members to generate an effective final product/output by providing essential components representing several ecosystem elements and social aspects that will later be combined to implement a food web model and a decision making model.
Albany Jacobson Eckert Jillian Mayer April Richards