False killer whales (Pseudorca crassidens) from Japan and South Africa: differences in growth and reproduction

Ferrira, Ines M., Kasuya, Toshio, Marsh, Helene, and Best, Peter B. (2014) False killer whales (Pseudorca crassidens) from Japan and South Africa: differences in growth and reproduction. Marine Mammal Science, 30 (1). pp. 64-84.

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Abstract

Age and reproductive information for 65 false killer whales stranded in South Africa in 1981 are compared with similar material from 156 animals examined from drive fisheries in Japan in 1979 and 1980. Sizes at birth, sexual maturation, and physical maturity all indicated that both sexes were 10%–20% larger in Japan than South Africa. Females reached sexual maturation at similar ages (8–10.5 yr) in both populations, and although sample sizes were too small to establish male ages at puberty precisely the ranges in Japan (10.5–18.5 yr) and South Africa (5.25–17.5 yr) were not inconsistent. The initial ovulation rate for females from South Africa was 65% lower (and the apparent pregnancy rate 82% lower) than those from Japan and there were fewer animals �2 yr old within the school, but the magnitude of these differences suggests that the stranded school’s reproductive performance was probably impaired. Collectively these comparisons and the literature indicate substantive size differences between false killer whales in different populations, although the patterns of growth appear similar. Firm conclusions about any geographical differences in reproduction require additional data.

Item ID: 38353
Item Type: Article (Research - C1)
ISSN: 1748-7692
Keywords: false killer whales; Pseudorca crassidens; age; growth; reproduction; North Pacific; South Atlantic
Funders: World Wide Fund for Nature, National Research Foundation, South Africa
Date Deposited: 14 May 2015 03:09
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 50%
04 EARTH SCIENCES > 0405 Oceanography > 040501 Biological Oceanography @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 75%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 25%
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