450 



Fishery Bulletin 102(3) 



South Island west coast, where an aerial survey of simi- 

 lar design resulted in an estimate of 5388 (CV=20.6 < *; 

 Slooten et al., in press). Thus Hector's dolphin abun- 

 dance in South Island waters is estimated at 7268 in- 

 dividuals (CV=15.8'7r ). The North Island subspecies of 

 Hector's dolphin, now considered critically endangered 

 (IUCN 4 ) remains to be surveyed quantitatively. 



The new abundance estimates provide an empirical 

 basis from which to calculate levels of take that would 

 still allow the currently depleted populations to recover 

 (e.g., Wade, 1998). These levels of take should be seen 

 as short-term targets for bycatch reduction in gill and 

 trawl nets. For the management of Hector's dolphin to 

 be put on a rational basis, a more comprehensive and 

 wide-ranging assessment of bycatch, including statisti- 

 cally robust observer programs in coastal fisheries, is 

 urgently needed. 



nificant contributions to equipment used in the survey- 

 were made by the New Zealand Whale and Dolphin 

 Trust and the University of Otago. We are very grateful 

 for the hard work put in by the other observers: Laszlo 

 Kiss, Nadja Schneyer, Gail Dickie, Niki Alcock, Lesley 

 Douglas, James Holborow, Ellie Dickson, Guen Jones, 

 Will Rayment, and Dan Cairney. Jay Barlow, Jeff Laake, 

 Anne York, and Debbie Palka shared their thoughts on 

 survey design and field methods. David Fletcher helped 

 with aspects of variance estimation. Akaroa Harbour 

 Cruises provided much appreciated field support. Daryl 

 Coup wrote the sightings program we used to collect 

 data in the field. Otago University's Department of 

 Surveying very helpfully provided the GPS base-station 

 data for postprocessing our GPS fixes. 



Literature cited 



Acknowledgments 



These surveys were funded principally by Department of 

 Conservation Contracts SCO 3072, 3074, and 3075. Sig- 



4 IUCN. 2000. IUCN red list of threatened species. In- 

 tel national Union for Conservation of Nature and Natural 

 Resources. Species Survival Commission. [Available at 



www.redlist.oru I 



Baird. S. J., and E. Bradford. 



2000. Estimation of the total bycatch of Hector's dolphins 

 Wcphalurhynchiis hectori) from the inshore trawl and 

 setnel fisheries off the east coast of the South Island in 

 the L997-98 fishing year. 28 p. Published client report 

 on contract 3024. funded by Conservation Services Levy, 

 Department of Conservation. Wellington. Web site: 

 http://csl.doc.govt.nz/CSL3024.pdf. [Accessed 8 March 

 2001.1 



