Estimates of stream residence time and escapement based on capture-recapture data

The area-under-the-curve method is a widely used method for estimating salm on escapement. The method depends on obtaining an accurate estimate of stre am residence time, or stream life. This paper develops an estimator of stre am residence time based on capture-recapture data. If the capture-recapture experiment is performed on the entire population, the escapement can also be estimated using the area-under-the-curve method. Simulations showed that the stream residence estimator and the area-under-the-curve estimator prov ide precise estimates of stream residence and escapement, respectively. The se methods were used to estimate the stream residence times and escapements of coho salmon (Oncorhynchus kisutch) in a small river on Vancouver Island in 1989 and 1990.