MEPS 420:263-271 (2010)  -  DOI: https://doi.org/10.3354/meps08857

Influence of feeding conditions on breeding of African penguins—importance of adequate local food supplies

Joël M. Durant1,*, Robert J. M. Crawford2,3, Anton C. Wolfaardt3,4,5,6, Kobus Agenbag2, Johan Visagie4, Leisha Upfold2, Nils Chr. Stenseth1,7

1Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway
2Oceans & Coasts, Department of Environmental Affairs, Private Bag X2, Rogge Bay 8012, South Africa
3Animal Demography Unit, Department of Zoology, University of Cape Town, Rondebosch 7701, South Africa
4CapeNature, Private Bag X29, Rondebosch 7701, South Africa
5Marine Research Institute, University of Cape Town, Rondebosch 7701, South Africa
6Joint Nature Conservation Committee, PO Box 585, Stanley, FIQQ 1ZZ, Falkland Islands
7Institute of Marine Research, Flødevigen Marine Research Station, 4817 His, Norway

ABSTRACT: Off the coast of South Africa, the 2 most important prey items for African penguins Spheniscus demersus are sardine Sardinops sagax and anchovy Engraulis encrasicolus, species heavily exploited by commercial fisheries. At Dassen Island, the proportion of burrows occupied for breeding by African penguins from 1995 to 2008 was affected positively by the interaction between the overall biomass of sardine and anchovy. However, sardine had a positive effect while anchovy had a negative one. This unexpected negative relationship may result from a reduced local availability of anchovy linked to the fishing effort that continued to be focussed in the vicinity of Dassen Island, while the growing anchovy stock experienced an eastward shift away from Dassen Island in recent years, creating a spatial mismatch between penguin and available anchovy. A decrease of the Southern Oscillation Index tended to advance the onset of penguins’ breeding, as did an increase in sea surface temperature (SST) at the sardine and anchovy spawning grounds. An increase in SST at the nursery and spawning areas tended to decrease the penguin per capita growth rate. Earlier breeding resulted in decreased chick production, possibly because it created a temporal mismatch between chick rearing and winter availability of young-of-the-year anchovy and sardine along South Africa’s west coast. The local abundance of prey is more important for breeding African penguins than overall fish abundance. Consequently, management of the purse-seine fishery should be adjusted spatially in order to ensure adequate local food supplies for breeding African penguins.


KEY WORDS: Breeding participation · Competition with fisheries · Conservation · Seabirds · Spatial management


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Cite this article as: Durant JM, Crawford RJM, Wolfaardt AC, Agenbag K, Visagie J, Upfold L, Stenseth NC (2010) Influence of feeding conditions on breeding of African penguins—importance of adequate local food supplies. Mar Ecol Prog Ser 420:263-271. https://doi.org/10.3354/meps08857

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