摘要：Multistate release–recapture models are used to study the movements and survival of animals when multiple migration pathways exist. Model complexity increases exponentially as the number of possible migration pathways increases. Program Branch was developed as freeware to allow users to construct multistate release–recapture models based on a schematic of the study design built with a graphic user interface (GUI). The GUI can be used not only to develop the underlying statistical likelihood models but to direct the estimation of summary performance parameters. Program Branch is illustrated using the spawning behavior of shortnose suckers (Chasmistes brevirostris) in northern California, juvenile Chinook salmon (Oncorhynchus tshawytscha) outmigration through the Sacramento–San Joaquin Delta of California, and adult steelhead (Oncorhynchus mykiss) migration in the Columbia/Snake River Basin in the Pacific Northwest. This software, available online at http://www.cbr.washington.edu/analysis/apps/branch , makes the analysis of complex multistate models easier and allows investigators to review study designs to ensure important model parameters are estimable.
