Decision-Support Tool Development

whitefish Sag Bay 106Decision-support tools help make decisions by incorporating information, accounting for uncertainties, or evaluating trade-offs between alternative choices.

Need for Such a Tool

Managers seek to maintain profitable and sustainable harvest of lake whitefish (in the 1836 Treaty waters). Currently, recommended harvest quotas for each management unit are calculated by statistical catch-at-age models that include estimates of population numbers, mortality rates, fishery harvest and other population parameters of interest (Deroba and Bence 2012). Environmental parameters are not included in the model.

Because the success of recruitment to the fishery has been linked with climatic influences, including water temperature, wind and ice cover (Miller 1952; Christie 1963; Lawler 1965; Taylor, Smalle et al. 1987; Freeberg, Taylor et al. 1990; Lynch, Taylor et al. 2010), there is concern that climate change may impact this fishery.

Stakeholder Input and Developing the Tool

This research project has engaged several stakeholder groups who are vested in the future of the lake whitefish fishery, including the 1836 Treaty Waters Technical Fisheries Committee and Modeling Subcommittee, the Great Lakes Fishery Commission, Michigan Department of Natural Resources, U.S. Fish & Wildlife  Service, Chippewa-Ottawa Resource Authority, Sault Ste. Marie Tribe, Bay Mills Tribe, Little River Band of Ottawa Indians, Grand Traverse Band of Ottawa and Chippewa Indians, and the Michigan Fish Producers Association.

The groups were asked to provide feedback via a survey. The outcomes of the survey were used to develop a user interface for the decision-support tool which incorporates environmental parameters — specifically water temperature, wind and ice cover — into the currently used statistical catch-at-age model.

If these parameters help improve population estimates, climate projections can be used to predict lake white fish production and distribution over ecologically relevant (i.e., generational) timescales.