African penguin populations have decreased 50% since 1978, due to nesting and guano collection disturbance, habitat alteration, oil pollution, and competition with fisheries for food.
Since the early 1900s, the African penguin population has been in decline. The population in Namibia declined from 12,162 pairs in 1978 to an estimated 5,800 pairs in 2015. The South African population declined from c. 70,000 pairs in 1978/79 (Shelton et al. 1984) to 19,300 pairs in 2015. In that year, the overall number of pairs was about 25,000 pairs, or 50,000 mature individuals. This roughly equates to about 80,000 individuals in adult plumage based on the conversion factor of 3.2 for pairs to individuals. Decreases in both countries amount to over 50% in three generations.
Initially, their decline was due to the disturbance of nesting birds and exploitation and commercial sale of their eggs for food. Also, habitat alteration and disturbance associated with guano collection at breeding colonies contributed to their decline.
These factors have now largely ceased, and the major current threats include oil pollution and competition with commercial fisheries for pelagic fish prey. Mortality also occurs in fishing nets when gill-nets are set near colonies.
There are no real negative economic effects of the African penguin on humans, however, as they do not eat enough fish to be detrimental to the local fishing industry.
Sources: (BirdLife International, 2016; Crawford & Boonstra, 1994; Crawford, et al., 2001; Frost, Siegfried, & Cooper, 1976; Hagen, 2014; Kemper, 2015; Pearce, 2011; Randall and Randall, 1990; Shannon & Crawford, 1999; Shelton, Crawford, Cooper, & Brooke, 1984; Stefoff, 2005)
Image: Kym Ellis