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Cited by 84Avian ecology and behaviorMarine animal studies overviewMarine and fisheries research

Distribution, population size and conservation of the jackass penguin Spheniscus demersus

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Shelton, P. A., Crawford, R. J. M., Cooper, J., Brooke, R. K.·1984·South African Journal of Marine Science
DOI 10.2989/02577618409504370
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Abstract

The jackass penguin, endemic to southern Africa, is the only member of the Sphenisciformes now breeding in Africa. Its breeding distribution extends from Sylvia Hill, South West Africa (Namibia), to Bird Island, Algoa Bay, South Africa. The non-breeding range extends from Sette Cama, Gabon, to Inhaca Island, Moçambique. Jackass penguins do not usually occur far off shore. The minimum total breeding population in 1978/79 was estimated to be approximately 134 000 birds. Numbers halved between 1956 and 1978 alone as a result of collapses in the South and South West African pilchard populations. Numerical decreases at Possession and Dassen Islands were particularly severe. Prior to 1956 numbers had also decreased, primarily because of large collections of eggs. Sealing activities and guano harvests may also have influenced trends. Only colonies at the periphery of the breeding distribution have increased numerically in recent times, and such increases appear to be related to the availability of suitable prey. Although the species breeds in captivity and is unlikely to become extinct, its continued survival in the wild probably relies on the continued good state of the pelagic fish resources.

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Authors
Shelton, P. A., Crawford, R. J. M., Cooper, J., & Brooke, R. K.
ORCID
Crawford, R. J. M.
Venue
South African Journal of Marine Science
Publisher
National Inquiry Services Center (NISC)
Published
1984-06
Volume
2
Issue
1
Pages
217-257
ISSN
0257-7615 (ISSN-L)
DOI
10.2989/02577618409504370
OpenAlex
W2035454980
Cited by
84
References
0
Citations by year
2026: 1 · 2025: 1 · 2024: 3 · 2023: 2 · 2021: 2 · 2020: 5 · 2019: 3 · 2018: 1 · 2017: 2 · 2016: 4 · 2015: 3 · 2014: 4 · 2013: 2 · 2012: 2
FWCI
6.02
Type
journal article
Language
en
Open access
Locations
South African Journal of Marine Science (publishedVersion)
Topics
  • Physical Sciences › Environmental Science › Ecology › Avian ecology and behavior
  • Physical Sciences › Environmental Science › Ecology › Marine animal studies overview
  • Physical Sciences › Environmental Science › Global and Planetary Change › Marine and fisheries research
Keywords
jackass penguin, Spheniscus demersus, breeding range, population size, population decline (ecology), seabird conservation, egg collection, sealing, prey availability, breeding colonies

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