Evaluating Creel Survey Efficiency for Estimating Walleye Fishery Metrics in Northern Wisconsin Lakes

Abstract

To determine whether creel survey efficiency can be improved in northern Wisconsin lakes, we compared estimates of effort, harvest rate, harvest, recapture rate for previously marked fish (R/C ratio), and recaptures of walleyes Sander vitreus from four reduced-sampling-effort schemes (eliminating 1 week per month, 2 weeks per month, odd-numbered weeks, and even-numbered weeks) in each month of the angling season with estimates from creel surveys during 1991–2002. Estimates of angler-hours from each reduced-sampling-effort scheme differed significantly from those from the full sampling effort in several months, and variances differed significantly in nearly all months. Estimates of walleyes harvested per hour from each reduced-sampling-effort scheme differed significantly from those from the full sampling effort only in May or June, and variances differed significantly in several months for all sampling effort schemes except that of 1 week per month. Estimates of walleye harvest from all reduced-sampling-effort schemes differed significantly from those from the full sampling effort for at most 2 months, but variances did not differ significantly in several months. Estimates of the R/C ratio from all reduced-sampling-effort schemes differed significantly from those from the full sampling effort for at most 2 months, but variances differed significantly in several months. Estimates of the number of recaptures differed significantly from those from the full sampling effort for several months with the elimination of 1 week per month and 2 weeks per month but did not differ significantly with the elimination of odd- or even-numbered weeks, and variances differed significantly in several months for all reduced-sampling-effort schemes. Creel survey efficiency cannot be improved using these sampling effort reductions without causing significant losses in accuracy and precision.