The Cape Fur seal (Arctocephalus pusillus pusillus) is the only pinniped resident to the South African coastline and breeds at 41 different sites between Baia dos Tigres in Angola and Algoa Bay in South Africa. Most of the colonies are situated on the west coast within the Benguela Current system, while only three are situated to the east of Cape Agulhas within the Agulhas Current system.
The Robberg Peninsula colony in Plettenberg Bay is one of the few situated in the Agulhas Current system and has only recently been considered as a breeding colony. A breeding colony is defined as a colony where at least 100 pups are born annually on a regular basis. Robberg Peninsula is currently home to over 6000 Cape Fur seals, but historically, before the start of commercial seal harvesting, it may have been home to many more.
Historically there were two colonies in Plettenberg Bay, one on Robberg Peninsula and another on Beacon Island. Unfortunately, these colonies were driven to extinction by the late 1800s as a result of indiscriminate and uncontrolled harvesting. After the introduction of protective legislation in 1893, Cape fur seals began recolonizing the area again in the 1990s. At first, only small numbers of seals returned to the area, but with time the numbers gradually increased, and in the breeding season of 1996/1997 the first newborn pups were observed on Robberg. Between 2000 and 2009, Cape Fur seal numbers on Robberg Peninsula steadily increased from less than 300 to over 3100, with a maximum number of 50 pups observed during the 2009 breeding season.
Although regular monthly counts of the number of seals hauled out on Robberg have been conducted by Cape Nature since 2009, the number of pups has not been monitored. However, recent independent boat-based counts during the 2016/2017 breeding season revealed 160-200 pups. Both the number of seals hauling out on Robberg, and the number of pups born annually, therefore, appears to be steadily increasing. Interestingly, so are the number of great white shark sightings in the area, possibly indicating an ecosystem recovering after many years of heavy commercial exploitation of not just seals, but also local fishery stocks.
Written by Danielle Conry and Frikkie van der Vyver
For further reading:
- HUISAMEN, J., KIRKMAN, S. P., WATSON, L. H., COCKCROFT, V. G. & PISTORIUS, P. A. 2011. Recolonisation of the Robberg Peninsula (Plettenberg Bay, South Africa) by Cape fur seals. African Journal of Marine Science 33(3): 453-461.