Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales

 

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dc.contributor.author Brandão, Anabela
dc.contributor.author Butterworth, Doug S
dc.date.accessioned 2016-04-04T09:28:53Z
dc.date.available 2016-04-04T09:28:53Z
dc.date.issued 2006
dc.identifier.citation Brandão, A., & Butterworth, D. S. (2006). Concerning demographic limitations on the population growth rate of West Australian (Breeding Stock D) humpback whales. International Whaling Commission document: SC/58/SH24, 1-15. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/18529
dc.description.abstract The upper bound of 0.126 on the maximum demographically possible annual population growth rate for humpback whales that is currently imposed on age-aggregated assessment models for this species, is based on an analysis that assumes steady age structure. It is conceivable that transient age-structure effects could admit greater population growth rates than suggested by such a bound for short periods. This possibility is addressed by developing an age-structured population model in which possible density dependent changes in pregnancy rate, age at first parturition and natural mortality are modeled explicitly, and allowance is made for the possibility of senescence. The model is applied to the case of the west Australian humpback whale population (breeding stock D), for which breeding ground surveys over the 1982-1994 period provide a point estimate of 0.10 for the annual population growth rate. Results based upon the breeding population surveys estimate of abundance of 10032 in 1999 suggest that 0.12 is the maximum feasible annual rate of increase for this stock over 1982-1994 if it is closed. This result is based on essentially the same parameter choices as led to the earlier r = 0.126 bound, viz. that in the limit of low population size the age at first parturition approaches 5 years from above, the annual pregnancy rate 0.5 from below, and the annual natural mortality rate 0.01 from above. en_ZA
dc.language eng en_ZA
dc.title Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales en_ZA
dc.type Journal Article en_ZA
dc.date.updated 2016-04-04T09:27:49Z
uct.type.publication Research en_ZA
uct.type.resource Research paper en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Resource Assessment and Management Group en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Brandão, A., & Butterworth, D. S. (2006). Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales. http://hdl.handle.net/11427/18529 en_ZA
dc.identifier.chicagocitation Brandão, Anabela, and Doug S Butterworth "Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales." (2006) http://hdl.handle.net/11427/18529 en_ZA
dc.identifier.vancouvercitation Brandão A, Butterworth DS. Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales. 2006; http://hdl.handle.net/11427/18529. en_ZA
dc.identifier.ris TY - Journal Article AU - Brandão, Anabela AU - Butterworth, Doug S AB - The upper bound of 0.126 on the maximum demographically possible annual population growth rate for humpback whales that is currently imposed on age-aggregated assessment models for this species, is based on an analysis that assumes steady age structure. It is conceivable that transient age-structure effects could admit greater population growth rates than suggested by such a bound for short periods. This possibility is addressed by developing an age-structured population model in which possible density dependent changes in pregnancy rate, age at first parturition and natural mortality are modeled explicitly, and allowance is made for the possibility of senescence. The model is applied to the case of the west Australian humpback whale population (breeding stock D), for which breeding ground surveys over the 1982-1994 period provide a point estimate of 0.10 for the annual population growth rate. Results based upon the breeding population surveys estimate of abundance of 10032 in 1999 suggest that 0.12 is the maximum feasible annual rate of increase for this stock over 1982-1994 if it is closed. This result is based on essentially the same parameter choices as led to the earlier r = 0.126 bound, viz. that in the limit of low population size the age at first parturition approaches 5 years from above, the annual pregnancy rate 0.5 from below, and the annual natural mortality rate 0.01 from above. DA - 2006 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2006 T1 - Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales TI - Concerning demographic limitations on the population growth rate of West Australian (breeding stock D) humpback whales UR - http://hdl.handle.net/11427/18529 ER - en_ZA


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