A GENERAL APPROACH TO TEMPORARY EMIGRATION IN MARKRECAPTURE ANALYSIS

During mark-recapture studies of open populations, animals often temporarily emigrate from study areas. Such temporary emigration can cause biased estimates of survival probabilities. We present a new statistical method to estimate survival probability from the capture histories of marked individuals in the presence of temporary emigration. This method uses stage-structured models that include one or more stages representing the individuals that have temporarily emigrated. Although not all parameters can be estimated in such stage structures, some important parameters are still estimable. Here, we determined the estimability of parameter values from the rank of the Jacobian of the likelihood function. We applied the temporary-emigration mark-recapture method to artificial data, representing various life histories and demonstrated consistency between actual and estimated values. As an example, we used the method to analyze data on reproductive female North Atlantic right whales. The method presented in this paper will be especially useful for studies of seabird, sea turtle, and marine-mammal populations where individuals are sampled only on their breeding grounds.

A GENERAL APPROACH TO TEMPORARY EMIGRATION IN MARKRECAPTURE ANALYSIS Academic Article