Modelling survival of Hector's dolphins around banks peninsula, New Zealand

In 1988, a marine mammal sanctuary was established around Banks Peninsula t o reduce Hector's dolphin entanglement in commercial and recreational gill nets. We describe the application of a multistate mark-recapture model to d ata from photographic identification surveys to determine the effect of the sanctuary on dolphin survival rates. The model allows sightings to occur i n three geographic strata with free movement between strata. Although we fo und evidence of both area and time effects on sighting probabilities we fou nd no evidence that survival rates depended on area or time. Thus, there wa s no evidence that dolphin survival rates increased following establishment of the sanctuary. However, power of this test is shown to be low.