An altered carrying capacity of the Benguela upwelling ecosystem for African penguins (Spheniscus demersus)

ICES Journal of Marine Science

Volumn 64, Issue 3, 2007, Pages 570-576

  Crawford, Robert J M ^a   Underhill, Les G ^b   Upfold, Leshia ^a   Dyer, Bruce M ^a  

^a Marine and Coastal Management ^*  (South Africa)

^b UNIVERSITY OF CAPE TOWN   (South Africa)

Author keywords

African penguin; Arctocephalus pusillus pusillus; Cape fur seal; Carrying capacity; Density dependence; Fishing; Food; Recruitment; Spheniscus demersus

Indexed keywords

CARRYING CAPACITY; DENSITY DEPENDENCE; FISHING; INTERSPECIFIC COMPETITION; PINNIPED; POPULATION VIABILITY ANALYSIS; UPWELLING; VULNERABILITY;

AFRICA; ANGOLA; BENGUELA; SOUTHERN AFRICA; SUB-SAHARAN AFRICA;

ARCTOCEPHALUS PUSILLUS PUSILLUS; AVES; SPHENISCIDAE; SPHENISCUS DEMERSUS;

EID: 34447501831     PISSN: 10543139     EISSN: 10959289     Source Type: Journal    
DOI: 10.1093/icesjms/fsm009     Document Type: Article

References (45)

1. BirdLife International. 2004. Threatened Birds of the World 2004. CD Rom version. BirdLife International, Cambridge, UK.
2. Butterworth, D. S., Punt, A. E., Oosthuizen, W. H., and Wickens, P. A. 1995. The effects of future consumption by the Cape fur seal on catches and catch rates of the Cape hakes. 3. Modelling the dynamics of the Cape fur seal, Arctocephalus pusillus pusillus. South African Journal of Marine Science, 16: 161-183.
3. Cairns, D. K. 1989. The regulation of seabird colony size: a hinterland model. American Naturalist, 134: 141-146.
4. Crawford, R. J. M. 1998. Responses of African penguins to regime changes of sardine and anchovy in the Benguela system. South African Journal of Marine Science, 19: 355-364.
5. Crawford, R. J. M., and Boonstra, H. G. V. D. 1994. Counts of moulting and breeding jackass penguins - a comparison at Robben Island, 1988-1993. Marine Ornithology, 22: 213-219.
6. Crawford, R. J. M., Boonstra, H. G. V. D., Dyer, B. M., and Upfold, L. 1995a. Recolonization of Robben Island by African penguins, 1983-1992. In The Penguins: Ecology and Management, 333-363. Ed. P. Dann, I. Norman, and P. Reilly. Surrey Beatty, Chipping Norton, Australia.
7. Crawford, R. J. M., David, J. H. M., Shannon, L. J., Kemper, J., Klages, N. T. W., Roux, J-P., Underhill, L. G. et al. 2001. African penguins as predators and prey - coping (or not) with change. South African Journal of Marine Science, 23: 435-447.
8. Crawford, R. J. M., David, J. H. M., Williams, A. J., and Dyer, B. M. 1989. Competition for space: recolonising seals displace endangered, endemic seabirds off Namibia. Biological Conservation, 48: 59-72.
9. Crawford, R. J. M., Dundee, B. L., Dyer, B. M., Klages, N. T. W., Meÿer, M. A., and Upfold, L. 2007. Trends in numbers of Cape gannets (Morus capensis), 1956/57-2005/06, with a consideration of the influence of food and other factors. ICES Journal of Marine Science, 64: 169-177.
10. Crawford, R. J. M., Dyer, B. M., Cooper, J., and Underhill, L. G. 2006a. Breeding numbers and success of Eudyptes penguins at Marion Island, and the influence of mass and time of arrival of adults. CCAMLR Science, 13: 175-190.
11. Crawford, R. J. M., Goya, E., Roux, J-P., and Zavalaga, C. B. 2006b. Comparison of assemblages and some life-history traits of seabirds in the Humboldt and Benguela systems. African Journal of Marine Science, 28: 553-560.
12. Crawford, R. J. M., Hemming, M., Kemper, J., Klages, N. T. W., Randall, R. M., Underhill, L. G., Venter, A. D. et al. 2006c. Molt of the African penguin, Spheniscus demersus, in relation to its breeding season and food availability. Acta Zoologica Sinica, 52 (Supplement): 444-447.
13. Crawford, R. J. M., Shannon, L. J., and Whittington, P. A. 1999. Population dynamics of the African penguin Spheniscus demersus at Robben Island, South Africa. Marine Ornithology, 27: 139-147.
14. Crawford, R. J. M., Shannon, L. V., and Pollock, D. E. 1987. The Benguela ecosystem. 4. The major fish and invertebrate resources. Oceanography and Marine Biology: An Annual Review, 25: 353-505.
15. Crawford, R. J. M., Underhill, L. G., Raubenheimer, C. M., Dyer, B. M., and Martin, J. 1992. Top predators in the Benguela ecosystem - implications of their trophic position. South African Journal of Marine Science, 12: 675-687.
16. Crawford, R. J. M., Williams, A. J., Hofmeyr, J. H., Klages, N. T. W., Randall, R. M., Cooper, J., Dyer, B. M. et al. 1995b. Trends of African penguin Spheniscus demersus populations in the 20th century. South African Journal of Marine Science, 16: 101-118.
17. Danchin, E., Boulinier, T., and Massot, M. 1998. Conspecific reproductive success and breeding habitat selection: implications for the study of coloniality. Ecology, 79: 2415-2428.
18. David, J. H. M. 1989. Seals. In Oceans of Life off Southern Africa, 288-302. Ed. by A. I. L. Payne and R. J. M. Crawford. Vlaeberg Publishers, Cape Town. 380 pp.
19. Forero, M. G., Tella, J. L., Hobson, K. A., Bertellotti, M., and Blanco, G. 2002. Conspecific food competition explains variability in colony size: a test in Magellanic penguins. Ecology, 83: 3466-3475.
20. Furness, R. W. 2002. Management implications of interactions between fisheries and sandeel-dependent seabirds and seals in the North Sea. ICES Journal of Marine Science, 59: 261-269.
21. Furness, R. W. 2006. Responses of seabirds to prey depletion. Journal of Ornithology, 147 (Suppl. 1): 14.
22. Halley, D. J., and Harris, M. P. 1993. Intercolony movement and behaviour of immature guillemots Uria aalge. Ibis, 135: 264-270.
23. Hockey, P. A. R., Dean, W. R. J., and Ryan, P. G. (Eds). 2005. Roberts Birds of Southern Africa, 7th edn. John Voelcker Bird Book Fund, Cape Town.
24. Kearton, C. 1931. The Island of Penguins. Longmans, Green and Co., London.
25. Kemper, J., Roux, J-P., Bartlett, P. A., Chesselet, Y. J., James, J. A. C., Jones, R., Wepener, S. et al. 2001. Recent population trends of African penguins Spheniscus demersus in Namibia. South African Journal of Marine Science, 23: 429-434.
26. Lewis, S., Grémilet, D., Daunt, F., Ryan, P. G., Crawford, R. J. M., and Wanless, S. 2006. Using behavioural and state variables to identify proximate causes of population change in a seabird. Oecologia, 147: 606-614.
27. Lewis, S., Sherratt, T. N., Hamer, K. C., and Wanless, S. 2001. Evidence of intra-specific competition for food in a pelagic seabird. Nature, 412: 816-819.
28. Miller, P. S., and Lacy, R. C. 2005. VORTEX: a Stochastic Simulation of the Extinction Process, Version 9.50. User's Manual. Conservation Breeding Specialist Group (SSC/IUCN), Apple Valley, MN.
29. Moss, R., Wanless, S., and Harris, M. P. 2002. How small northern gannet colonies grow faster than big ones. Waterbirds, 25: 442-448.
30. Petersen, S. L., Ryan, P. G., and Gremillet, D. 2005. Is food availability limiting African penguins at Boulders?: a comparison of foraging effort at mainland and island colonies. Ibis, 147: 14-26.
31. Rand, R. W. 1960. The biology of guano-producing seabirds. The distribution, abundance and feeding habits of the Cape penguin, Spheniscus demersus, off the south-western coast of the Cape Province. Investigational Report Division of Fisheries, South Africa, 41. 28 pp.
32. Rand, R. W. 1963a. The biology of guano-producing seabirds. 4. Composition of colonies on the Cape Islands. Investigational Report Division of Sea Fisheries, South Africa, 43. 32 pp.
33. Rand, R. W. 1963b. The biology of guano-producing seabirds. 5. Composition of colonies on the South West African islands. Investigational Report Division of Sea Fisheries, South Africa, 46. 26 pp.
34. Randall, R. M. 1989. Jackass penguins. In Oceans of Life off Southern Africa, pp. 244-256. Ed. by A. I. L. Payne and R. J. M. Crawford. Vlaeberg Publishers, Cape Town. 380 pp.
35. Randall, R. M., Randall, B. M., Cooper, J., and Frost, P. G. H. 1986. A new census method for penguins tested on jackass penguins Spheniscus demersus. Ostrich, 57: 211-215.
36. Shannon, L. J., and Crawford, R. J. M. 1999. Management of the African penguin Spheniscus demersus - insights from modelling. Marine Ornithology, 27: 119-128.
37. Shaughnessy, P. D. 1980. Influence of Cape fur seals on jackass penguin numbers at Sinclair Island. South African Journal of Wildlife Research, 10: 18-21.
38. Shaughnessy, P. D. 1984. Historical population levels of seals and seabirds on islands off southern Africa, with special reference to Seal Island, False Bay. Investigational Report Sea Fisheries Research Institute, South Africa, 127. 61 pp.
39. Underhill, L. G., and Crawford, R. J. M. 1999. Season of moult of African penguins at Robben Island, South Africa, and its variation, 1988-1998. South African Journal of Marine Science, 21: 437-441.
40. Underhill, L. G., Crawford, R. J. M., Wolfaardt, A. C., Whittington, P. A., Dyer, B. M., Leshoro, T. M., Ruthenberg, M. et al. 2006. Regionally coherent trends in colonies of African penguins Spheniscus demersus in the Western Cape, South Africa, 1987-2005. African Journal of Marine Science, 28: 697-704.
41. Westphal, A., and Rowan, M. K. 1971. Some observations on the effects of oil pollution on the jackass penguin. Ostrich (Suppl.), 8: 521-526.
42. Whittington, P. A. 2002. Survival and movements of African penguins, especially after oiling. PhD thesis, University of Cape Town.
43. Whittington, P. A., Klages, N. T. W., Crawford, R. J. M., Wolfaardt, A. C., and Kemper, J. 2005a. Age at first breeding of the African penguin. Ostrich, 76: 14-20.
44. Whittington, P. A., Randall, R. M., Crawford, R. J. M., Wolfaardt, A. C., Klages, N. T. W., Randall, B. M., Bartlett, P. A. et al. 2005b. Patterns of immigration to and emigration from breeding colonies by African penguins. African Journal of Marine Science, 27: 205-213.
45. Whittington, P. A., Randall, R. M., Randall, B. M., Wolfaardt, A. C., Crawford, R. J. M., Klages, N. T. W., Bartlett, P. A. et al. 2005c. Patterns of movement of the African penguin in South Africa and Namibia. African Journal of Marine Science, 27: 215-229