The influence of food availability on breeding success of African penguins Spheniscus demersus at Robben Island, South Africa

RJM Crawford, PJ Barham, LG Underhill, LJ Shannon, J Coetzee, BM Dyer, TM Leshoro, L Upfold

Research output: Contribution to journalArticle (Academic Journal)

75 Citations (Scopus)

Abstract

From 1989 to 2004, the breeding success of African penguins Spheniscus demersus at Robben Island, South Africa was significantly related to estimates of the abundance of both their main prey species, anchovy Engraulis encrasicolus and sardine Sardinops sagax, and to the combined biomass of these species. When the combined spawner biomass of fish prey was less than 2 million ton, pairs fledged an average of 0.46 chicks annually. When it was above 2 million ton, annual breeding success had a mean value of 0.73 chicks per pair. Given previously estimated values of survival and age at first breeding, these levels of breeding success are inadequate to sustain the African penguin population. With the higher level of breeding success, an equilibrium situation might be attained if adult survival could be increased by 6–7% per annum. Attempts to reduce mortality of penguins have included the collection, cleaning and return to the wild of oiled birds, culling of Cape fur seals Arctocephalus pusillus pusillus seen preying on penguins around breeding localities and control of the spread of disease. Management of the purse-seine fishery should ensure adequate escapement of fish to maintain the combined biomass of anchovy and sardine above 2 million ton. The maintenance of suitable breeding habitat and removal of feral predators from breeding localities will also be important in improving breeding success.
Translated title of the contributionThe influence of food availability on breeding success of African penguins Spheniscus demersus at Robben Island, South Africa
Original languageEnglish
Pages (from-to)119 - 125
Number of pages7
JournalBiological Conservation
Volume132 (1)
DOIs
Publication statusPublished - Sep 2006

Bibliographical note

Publisher: Elsevier Science B.V

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