A Classical Study of Catch-Effort Models for Hector's Dolphins

Ruth King and Stephen P. Brooks

Universities of St. Andrews and Cambridge


Effective management is the key to the protection of many endangered species. Identification of the primary factors affecting their survival will often lead to the introduction of strategies to improve survival rates. In this paper, we consider a small population of Hector's dolphins located off the coast of New Zealand and the impact that the establishment of a seasonal sanctuary has on their survival and migration rates. Using Akaike's information criterion and an extension of the simulated annealing algorithm, we distinguish between a wide range of competing models corresponding to different assumptions as to the spatial and temporal dependence of the survival rates. We also examine the impact of the inclusion of catch-effort information and demonstrate the added value that these data provide in terms of both model discrimination and parameter estimation. In particular, we find a whole class of models that provide a far better fit to the data (and therefore better prediction and ultimately better management) than those adopted for previous analyses.


Akaike's Information Criterion; Capture-recapture; Model Selection; Parameter Estimation; Trans-Dimensional Simulated Annealing.

Appeared as King, R. and Brooks, S. P. (2004) "A Classical Study of Catch-Effort Models for Hector's Dolphins". Journal of the American Statistical Association 99 pp 325-333.