Evaluation of Lake Whitefish (Coregonus clupeaformis) Growth and Relative Abundance using Fishery Independent Surveys: Implications for Setting Harvest Limits
Robin DeBruyne
Lake whitefish (Coregonus clupeaformis) have historically been an important commercial fishery in Michigan. In the 1950’s there was a decline in the commercial fishery due to overfishing and predation by sea lamprey. The numbers restored themselves in the 1970’s and catch-at-age models have been developed for lake whitefish from commercial fishery data. An independent lake whitefish survey (conducted by state and tribal governments) was needed to improve the accuracy of these models. Lake whitefish were collected from Lake Michigan with bottom gill nets by the MI DNR. By using the scales provided by the MI DNR, I will be aging the scales and back-calculating length-at-age for the lake whitefish and comparing relative growth rates between cohorts. By evaluating relative growth rates using multiple-regression and partial correlation techniques, possible environmental factors influencing growth could be identified. Relative abundance will also be determined from the catch rates. This information will be incorporated into the current lake whitefish models to improve accuracy and help to set future commercial harvest limits.