Simulation testing of the sabbatical model estimator for the assessment of Southern Hemisphere humpback whale breeding Stock  C and its component Sub-stocks

Johnston, Susan J; Butterworth, Doug S; Muller, A

Simulation testing of the sabbatical model estimator for the assessment of Southern Hemisphere humpback whale breeding Stock C and its component Sub-stocks

Working Paper

2009

Publisher

University of Cape Town

Department

Marine Resource Assessment and Management Group

Faculty

Faculty of Science

Abstract

Johnston and Butterworth (2009) implement four models (Resident, Sabbatical, Tourist and Migrant) to estimate parameters for the C1 and C3 substocks, including the probability of interchange between them, using a Bayesian approach which takes account of capture-recapture information from photo-id data. This estimator generally captures the underlying parameter values reasonably, though with a tendency to estimate r too low and K too high. Interchange rates are also reasonably estimated, both when the true rates are low and high. In the latter case, abundance estimates in terms are lower. Here a range of Operating Models (OMs) are defined and used to test the Sabbatical estimator