A sensitivity analysis to guide research and management for Hector's dolphin

Hector's dolphin (Cephalorhynchus hectori) is an uncommon endemic of New Ze aland which is suspected to be in decline due to entanglement mortality. Ho wever, uncertainty in available data has led to a dispute between the New Z ealand Ministry of Fisheries and the New Zealand Department of Conservation over the status of this species. We use a density-dependent deterministic model to predict the future abundance and geographic distribution of Hector 's dolphin under different scenarios of fisheries management. We then exami ne the sensitivity of this model to a number of parameters for which few or no data are available. We find that two populations of Hector's dolphins a re predicted to decline in the future even when the most optimistic paramet er estimates are used. The status of the third population is dependent upon the estimate of maximum annual population growth rate. Because of the depe ndence of final abundance estimates on the estimates of entanglement mortal ity rates and maximum population growth rate, research efforts should be co ncentrated on estimating these parameters. (C) 1999 Published by Elsevier S cience Ltd. All rights reserved.