Cohort Analysis as an Indication of Walleye Year-Class Strength in Escanaba Lake, Wisconsin, 1956–1974

Cohort analysis of catch-at-age data derived from the angler harvest of walleyes Stizostedion vitreum vitreum under a complete creel census in Escanaba Lake yielded estimates of the number of walleyes at various ages for the 1956–1974 year classes. These estimates of the number-at-age were highly correlated with mark-recapture estimates, indicating the validity of the cohort analysis technique. Where long-term catch-at-age data are available, the cohort analysis method to determine number-at-age of previous year classes may be used in lieu of costly mark-recapture experiments.