Rationale
(Changed due to Genuine (recent))
The previously abundant Cape Cormorant Phalacrocorax capensis now satisfies the population size criterion A2 for regionally Endangered (an observed, estimated, inferred, or suspected population size reduction of ≥50% over the last three generations where the reduction or its causes may not have ceased or may not be understood or may not be reversible). In addition, it is suspected that this decline will continue into the future satisfying criteria A3 and A4.
Distribution
The Cape Cormorant is endemic to southern Africa, occurring from Lobito, central Angola, to Maputo Bay, southern Mozambique with its core range being from Cape Cross, northern Namibia to Cape Agulhas, Western Cape (Cooper et al. 1982). Its breeding range extends from Ilha dos Tigres, southern Angola to Bird Island, Eastern Cape (Crawford 1997). It is a regular visitor to the coasts of KwaZulu-Natal, mainly between July and November and is a winter visitor to southern Angola (Brooke 1981).
Population
The global population has been quantified at c. 144 000 mature individuals (BirdLife International 2014). In 2011, the regional population comprised of 74 816 mature individuals compared to 106 479 pairs or 213 000 breeding birds in 1978 (Crawford et al. 2012). The confidence in this regional population estimate is high.
Population trend
The regional population is in decline. Between 1985 and 2011 (26 years, i.e. 3 generations before 2011), the population decreased by 57.4% at the six main breeding islands. To account for short-term natural inter-annual variation in numbers, bird counts for 1985 were calculated as the average over a 4 year period (1985-1988: 155 392 mature individuals) and bird counts for 2011 were also calculated as the average over a 4 year period (2008-2011: 66 242 mature individuals; Crawford et al. 2012). The regional population is suspected to be declining in excess of the 50% threshold and this decline will continue. The confidence in this regional population trend estimate is high.
Threats
The number of breeding pairs at any time has been shown to depend directly on available food biomass, and in particular anchovies and sardines. Prey biomass is known to fluctuate from year to year and the sardine population has undertaken an eastward shift in the 2000s, possibly due to climate change. This shift may explain some of the decline observed on the West Coast (Crawford et al. 2007). Depletion of local resources by purse-seine fisheries is also thought to be partly responsible for the negative trends observed, particularly over a longer period and mainly for colonies on the West Coast; this hypothesis requires further investigation. The species is very sensitive to human disturbance, which leads to nest desertion and loss of eggs and chicks to avian predators. The increase in numbers of Kelp Gulls Larus dominicanus may decrease the breeding success in some areas through increased predation on eggs and chicks (Voorbergen et al. 2012). Great White Pelicans Pelecanus onocrotalus are a threat on islands off the West Coast, predating large amounts of average to large size chicks (Mwema et al. 2010). A serious threat is the Cape Fur Seal Arctocephalus pusillus, which can predate up to 24% of all fledglings produced by a single breeding colony (Voorbergen et al. 2012) and which are increasing in numbers. Worryingly, about 65% of the South African population breeds at just one locality, Dyer Island, where large outbreaks of avian cholera Pasteurella multocida caused substantial mortality of Cape Cormorants in the early 2000s (Waller and Underhill 2007). Avian cholera also caused mortalities at Dassen Island and Lambert's Bay. The species is vulnerable to oiling, and attempts to catch and clean oiled birds have generally been unsuccessful in the past.
Conservation
Underway
Current conservation actions involve only full protection of breeding colonies of Cape Cormorants, i.e. mainly islands, which fall under the jurisdiction of South African National Parks, CapeNature and Robben Island Nature Reserve. Trends in numbers breeding at important colonies are being monitored by Department of Environmental Affairs, CapeNature and SANParks. Opportunistic information on diet is obtained. Banding of chicks is undertaken to estimate movements and survival. The species is protected in terms of the Sea Birds and Seals Protection Act No. 46 of 1973.
Proposed
A Population and Habitat Viability Assessment (PHVA) is recommended, as is a Biodiversity Management Plan, culminating in a National Species Recovery Plan. Conservation research should focus more specifically on investigating and efficiently addressing the food shortage hypothesis. Although fishing is suspected to be partly responsible for the decline of Cape Cormorant numbers, this remains difficult to demonstrate. Future research should concentrate on exploring how different indexes of fish abundance, including catch biomass, at different geographical and temporal scales influence population dynamics at different colonies. It is important that food is secured in the vicinity of important colonies, especially Dyer Island, and that spread of disease continues to be restricted. This work should link explicitly to similar work, for similar objectives, being undertaken for other threatened near-endemic colonial seabird species, such as the African Penguin Spheniscus demersus and Cape Gannet Morus capensis.
Research
Research is under way at Percy FitzPatrick Institute of African Ornithology, focusing on foraging strategies and the building of energetic models of Cape Cormorants. Present research focuses on understanding how Cape Cormorants explore their environment in search of food.
* The role of competition from the small pelagic fishery in driving the current decreases should be investigated.
* Foraging ranges around breeding colonies (for potential fishing closures during breeding) would be helpful, as would an understanding of birds' at-sea distribution and overlap with fishing effort outside the breeding season.
