Sampling nearshore estuarine fishes with rotenone

Sampling with rotenone is an effective method for providing abundance estimates of estuarine fishes at nearshore locations. However, the determination of recovery rates for individual species is critical for estimating abundance by this technique. Recovery rates in this study varied greatly among species, but did not vary among station types (cove or shoreline) or sample years (1976 or 1977). Tagged fishes, used to establish recovery rates, did not change in weight due to the sampling procedures from time of introduction to time of collection. Total adjusted abundance estimates ranged from 157 to 18,300 fishes/hectare and from 36 to 4080 kg/hectare for fishes greater than 124 mm in Texas estuaries. Mean number and weight of fishes per hectare were generally greater at cove stations than at shoreline stations. Timing for the application of rotenone in estuaries is important to avoid extensive bird predation.