Variability of Electrofishing Crew Efficiency, and Sampling Requirements for Estimating Reliable Catch Rates

Abstract

Abstract Comparisons of electrofishing catch rates were conducted on two lakes in central Florida; sampling precision was examined in five other lakes. Significant differences were found among crews for various sizes (adults, subadults, quality) of largemouth bass Micropterus salmoides, bluegill Lepoinis inacrochirus, and redear sunfish L. microlophus. Results were not consistent between lakes, and rankings of crew catches varied among size categories. The number of samples required to estimate largemouth bass catch per minute with confidence limits that are within 10% of the mean at the 80% confidence level ranged from 4 to 110 (median, 19), based on catch rates from seven central Florida lakes. From 2 to 28 samples (median, 5) would be required to estimate largemouth bass catch per unit effort within 20% of the mean. For bluegill, the number of samples required to yield confidence limits within 20% of the mean ranged from 4 to 83 (median, 17). Precision ofwithin 20% ofthe mean is recommended for fisheri...