Modeling juvenile salmon migration using a simple Markov chain

We describe movement patterns of hatchery-raised, juvenile, spring chinook salmon, Oncorhynchus tshawytscha, using a two-state Markov chain model. The existence of two states, moving and holding, is suggested by anecdotal inf ormation from a large radio telemetry study; yet adequate observations of t hese small-scale fish behaviors are not available for estimating transition probabilities directly. Instead, we estimate the transition probability ma trix from travel times within each of II river segments using a method of m oments approach. Bootstrapped confidence intervals are presented. Results s uggest that fish behavior in the region of the confluence between the Grand e Ronde and Snake Rivers includes many transitions between moving and stayi ng while fish behavior in the Snake River is more likely to include long pe riods of staying.