Evaluating seal–seabird interactions in southern Africa: a critical review

Abstract

Through predation and displacement, the Cape fur seal Arctocephalus pusillus pusillus poses a threat to several seabird species that breed in southern Africa. Measures such as the culling of ‘problem’ seals have been introduced to negate the effects on these species, but there have been calls for stronger measures to be taken against seals. In this review, past evidence for direct impacts of seals on seabird populations was scrutinised. It was found that frequently the interpretation of seabird numer ical trends, or of anecdotes on seal–seabird interactions, appear biased against seals. It is mooted that, as with seal–fishery interactions, the conspicuous nature of seals and some of their behaviour may have resulted in their effects on seabird colonies or populations being overemphasised in the past. The poor conservation status of the impacted seabird species has been influenced by numerous factors, foremost of which are human interference and historical bad management practices. Culling or displacing of seals, at any scale, are unlikely to reverse trends in declining populations of seabirds, especially if conducted in isolation of other management actions, such as measures to enhance or expand the breeding habitat of seabirds.

Keywords: African penguin; Cape fur seal; Cape gannet; competition; conservation; culling; displacement; management; predation; seal–seabird interactions; southern Africa

African Journal of Marine Science 2009, 31(1): 1–18