Estimation of survival rates from sightings of individually identifiable whales

Makes particular reference to bias as a result of heterogeneity in the probabilities of sighting between animals. Natural markings data on Atlantic Megaptera novaeangliae are used to illustrate the approach. Annual survival rate of the Gulf of Maine stock is estimated to be 0.951, with standard error 0.010 and 95% confidence interval (0.929, 0.969). -from Author