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Releasability Appendix E

IWC Special Report 12

Abstract
(longevity in the wild)

International
Whaling
Commission

Individual Recognition of Cetaceans:
Use of Photo-Identification and Other Techniques
to Estimate Population Parameters

INCORPORATING THE PROCEEDINGS OF THE
SYMPOSIUM AND WORKSHOP ON INDIVIDUAL RECOGNITION
AND THE ESTIMATION OF CETACEAN POPULATION PARAMETERS

Edited by

Philip S. Hammond
Sea Mammal Research Unit, c/o British Antarctic Survey
Madingley Road, Cambridge, CB3 OET, UK

Sally A. Mizroch
National Marine mammal Laboratory, 7600 Sand Point Way NE, BIN C 15700
and Gregory P. Donovan
The International Whaling Commission
The Red House, Station Road, Histon, Cambridge, CB4 4NP, UK

Series Editor
Gregory P. Donovan

1990

Report of the International Whaling Commission
Special Issue 12

Life history parmaters are derived for the resident from of killer whale in the coastal waters of British Columbia and Washington State based on the demographic changes observed in two communities (closed to immigration and emigration) that were monitored between 1973-4 and 1987. Females have a mean life expectancy of 50.2 years, typically give birth to their first viable calf at 14.9 years of age, produce an average of 5.35 viable calves over a 25.2 year reproductive lifespan and have a maximum longevity of about 80-90 years. Calving is diffusely seasonal with most births occurring in October-March. Neonate mortality is approximately 43%. The estimated proportion of mature females pregnant varies from 0.274 in April to 0.411 in September. Males have a mean life expectancy of 29.2 years, typically attain sexual maturity at 15.0 years and physical maturity at 21.0 years of age, and have a maximum longevity of about 50-60 years. Mortality curves are U-shaped for both females and males, but the curve is narrower for males. There is no evidence of density dependence in the life history parameters as a result of cropping prior to the start of the study or as the populations increased during the study.

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Appendix D | Contents | Appendix F

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