Seining effort needed to detect changes in relative abundance of common littoral zone fishes in Wyoming reservoirs

Fisheries scientists often use beach seines to determine species presence and to estimate relative abundance of small littoral zone fishes in lentic habitats. My purposes were to estimate the effort needed to detect various changes in relative abundance of common littoral zone fishes and to determine the degree of change likely to be detected with a realistic amount of effort at various combinations of alpha and beta for three reservoirs in Wyoming. Retrospective power analysis was conducted on relative abundance data from 75 randomly selected 33-m seine hauls for each reservoir. The detection of large-to-moderate changes (50% to 25% from the mean) in relative abundance typically are not logistically possible with seining and reasonable amounts of seining (15 seine hauls) typically allow the detection of 75% or greater changes from the mean. Seining is an ineffective tool for measuring and detecting large changes in relative abundance of small littoral zone fishes.