Collapse of South Africa's penguins in the early 21st century

The number of African penguins Spheniscus demersus breeding in South Africa collapsed from about 56 000 pairs in 2001 to some 21 000 pairs in 2009, a loss of 35 000 pairs (>60%) in eight years. This reduced the global population to 26 000 pairs, when including Namibian breeders, and led to classi...

Full description

Saved in:
Bibliographic Details
Published in:African journal of marine science 2011-04, Vol.33 (1), p.139-156
Main Authors: Crawford, RJM, Altwegg, R, Barham, BJ, Barham, PJ, Durant, JM, Dyer, BM, Geldenhuys, D, Makhado, AB, Pichegru, L, Ryan, PG, Underhill, LG, Upfold, L, Visagie, J, Waller, LJ, Whittington, PA
Format: Article
Language:English
Subjects:
African penguin
Animal populations
diet
Engraulis encrasicolus
Marine
numbers breeding
numbers moulting
Sardinops sagax
Spheniscus
Spheniscus demersus
survival
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The number of African penguins Spheniscus demersus breeding in South Africa collapsed from about 56 000 pairs in 2001 to some 21 000 pairs in 2009, a loss of 35 000 pairs (>60%) in eight years. This reduced the global population to 26 000 pairs, when including Namibian breeders, and led to classification of the species as Endangered. In South Africa, penguins breed in two regions, the Western Cape and Algoa Bay (Eastern Cape), their breeding localities in these regions being separated by c. 600 km. Their main food is anchovy Engraulis encrasicolus and sardine Sardinops sagax, which are also the target of purse-seine fisheries. In Algoa Bay, numbers of African penguins halved from 21 000 pairs in 2001 to 10 000 pairs in 2003. In the Western Cape, numbers decreased from a mean of 35 000 pairs in 2001-2005 to 11 000 pairs in 2009. At Dassen Island, the annual survival rate of adult penguins decreased from 0.70 in 2002/2003 to 0.46 in 2006/2007; at Robben Island it decreased from 0.77 to 0.55 in the same period. In both the Western and Eastern Cape provinces, long-term trends in numbers of penguins breeding were significantly related to the combined biomass of anchovy and sardine off South Africa. However, recent decreases in the Western Cape were greater than expected given a continuing high abundance of anchovy. In this province, there was a south-east displacement of prey around 2000, which led to a mismatch in the distributions of prey and the western breeding localities of penguins.
ISSN:1814-232X
1814-2338
DOI:10.2989/1814232X.2011.572377