Catch-per-unit-effort (CPUE) data for lake whitefishCoregonus clupeaformisin Michigan waters of Lake Huron were examined with time analysis to test if they can describe the abundance of lake whitefish. Relations between lake whitefish CPUE and environmental and biological data were investigated with cross-correlation analysis. A 4-year time lag, corresponding to the age at maturity, was found for lake whitefish CPUE. Cross-correlation analysis indicated that lake whitefish CPUE was negatively correlated with monthly air temperatures and abundance of sea lampreyPetromyzon marinusin previous years, and CPUE was positively correlated with fishing effort 1 year later. The results indicated that fishermen track lake whitefish abundance and that CPUE can describe fluctuations of the lake whitefish population.