Brown Trout Population Dynamics and Angling Behavior in New York Streams: Evaluation of a Stocking Model

Brown trout (Salmo trutta) stocking has a long history in New York and fishing for trout generates millions of dollars for the state. The Catch Rate Oriented Trout Stocking (CROTS) model aims to provide anglers a catch rate of 0.5 fish per hour and is based on several assumptions including natural mortality rate, angler effort, catch and harvest rate, as well as wild trout densities and carrying capacity. The goal of this ongoing study is to test several CROTS model assumptions and to bring New York state trout stocking practices into alignment with current knowledge of trout population dynamics and angler pressure patterns. Three-pass electrofishing depletion population surveys and angler creel surveys were conducted on eight streams around the state to determine angler effort (hours), catch per unit of effort (CPUE), harvest rates, and wild and stocked trout densities. Instantaneous daily mortality rates (Zn) were modeled using the decline in trout density over time. In all streams, angler effort had decreased from the original CROTS model input estimates, though differences were not significant. Harvest rates decreased from an assumed 100% to an average of 22%. Daily and annual Zn were significantly higher for 2011 than the assumed CROTS  rate.