New Zealand Journal of Marine and Freshwater Research abstracts
Population viability analysis for Hector’s dolphin (Cephalorhynchus
hectori): a stochastic population model for local populations
Stephanie M. Burkhart*
Elisabeth Slooten
Environmental Science
University of Otago
P.O. Box 56, Dunedin
New Zealand
email: Liz.Slooten@stonebow.otago.ac.nz
*Present address: Coast Guard Pacific Area, Coast Guard Island,
Bldg 51-5, Alameda, CA 94501- 5100, United States.
email: sburkhart@d11.uscg.mil
Abstract Mortality of Hector’s dolphin (Cephalorhynchus
hectori) in gill-net fisheries is a threat to local populations throughout
its range. This population viability analysis extends previous work by exploring
a wider range of fishing levels and population growth rates, by incorporating
year-to-year and environmental variability and by reporting results for smaller
population units. Ten of the 16 populations are likely to continue to decline,
five are indefinite, and one is likely to increase. All populations subjected
to high fishing effort are declining. The only population predicted to increase
is partly protected by a marine mammal sanctuary (created in 1988) which
reduces the amount of gill-net fishing. Conservation measures are most urgently
needed for the highly threatened North Island population, in particular the
dolphins at the northern and southern end of this range.
Keywords Hector’s dolphin; population viability analysis;
PVA; extinction risk; gill-net entanglement; bycatch; environmental impacts
of fishing
M02041 Received 7 June 2002; accepted 30 January 2003; Published 5 August
2003
New Zealand Journal of Marine and Freshwater Research, 2003, Vol. 37:
553-566
0028-8330/03/3702-0553 $7.00 © The Royal Society of New Zealand
2003
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