Capture-Recapture Studies using Radio Telemetry with Premature Radio-Tag Failure

Summary. Radio-tags are often used in capture-recapture studies because of their high detectability. A key assumption is that radio-tags do not cease functioning during the study. Radio-tag failure before the end of a study can lead to underestimates of survival rates. We develop a model to incorporate secondary radio-tag failure data. This model was applied to chinook smolts (Oncorhynchus tshawytscha) on the Columbia River, WA. Estimates of sh survival from this model were much larger than those from the standard Cormack-Jolly-Seber analysis. 1