POCKETS OF SAFETY
Islands, Eilande, Iziqithi, Iziqhinga
Safe spaces where threatened seabirds like penguins and gannets can nest and feed their chicks
Photo: Peter Chadwick
What are Islands?
Islands are isolated pieces of land, surrounded by the sea. South Africa has at least 30 coastal islands off spread around the West and South Coasts.
Surrounded by a productive marine environment, islands are sanctuaries for seabirds and seals. Many species of seabirds breed on coastal islands, including Endangered African Penguins and Cape Gannets. The isolated nature of islands protects them from direct human disturbances like trampling and coastal development. Seabirds can also nest safely without the threat of mainland predators like caracal, mongooses and domestic cats. Additionally, many seabird islands and the surrounding seas are Marine Protected Areas to conserve the threatened species breeding on the islands.
The seabird colonies on islands produce guano (nutrient-rich faeces), which washes off into the surrounding sea, making it an extremely nutrient-rich environment for marine species to grow. This higher productivity enables more food to be available for filter feeders and encourages seaweed growth, thereby boosting the size and abundance of grazers.
Marion and Prince Edward Island
Sub-Antarctic island sanctuary
South Africa has an offshore island territory in the Southern Ocean. Two islands, Marion Island and Prince Edward Island, are critical conservation areas for species that occur nowhere else on mainland South Africa.
A small group of scientists lives on Marion Island for 13 months at a time, conducting important research on the seabirds, seals, killer whales and other biological interactions taking place at the islands.
© Robyn Adams
Both Islands are important conservation areas for seabirds and seals. Several species of albatross, petrels and penguins (King and Rockhopper penguins) as well as Crozet Shags breed on the islands. There are also large breeding colonies of Elephant seals and sub-Antarctic fur seals.
The Islands are under pressure from invasive species, where introduced mice have been severely affecting seabird populations. To learn more about projects to eradicate mice, visit Mousefreemarion.org
Who lives on Islands?
Large colonies of seabirds and sometimes cape fur seals live and breed on islands where they are safe from the threat of mainland predators. Some of the seabird species living on South Africa’s Islands include African penguins, Gulls (kelp gulls and Hartlaub’s gulls), Terns (roseate, Swift and Caspian terns), Cape gannets, Cormorants (bank cormorants, Cape cormorant, crowned cormorants, white-breasted cormorants) and African Black Oystercatchers.
Surrounding islands is a biodiversity-rich marine environment with larger populations of the species usually found along the mainland coast. Islands with large seal populations attract white sharks, bronze whaler sharks and other predators.
Why are Islands important?
Islands provide safe places for seabirds to rest and breed. The population numbers of many of the seabird species, who live on these islands, have been declining. African penguins, Cape gannets, Cape cormorants and bank cormorants are listed as endangered by the International Union for the conservation of nature (IUCN).
Many mainland penguin colonies have suffered due to disease and mainland predators like caracal and domestic cats. Island populations may be the last chance these birds have for recovery. Islands are also important tourism assets. Boat-based tour operators take tours to islands so that visitors can see the abundant marine life attracted to islands like seals, sharks and whales.
How do we care for Islands?
The birds breeding on islands are under threat from climate change and may struggle to find enough fish food close to their breeding area. Seabirds eat forage fish like sardines and anchovy which are also important species for the small pelagic fishery.
Caring for islands requires us to:
Prevent and manage invasive species- In South Africa’s sub-Antarctic territory of the Prince Edward islands, invasive species are the largest threat to breeding albatross populations. The invasive house mouse feeds on albatross chicks in their nests and has significantly reduced the albatross population on Marion Island. One of the largest eradication programs in the world is currently underway to remove mice from the island and ensure population recovery of albatross. It is critical that invasive species are prevented from accessing island systems and where invasives occur, management is needed. Prevent new marine invasions through monitoring response planning, ring-fenced resources and rapid management action.
Protect Islands and manage surrounding areas– Islands are important areas for South Africa’s tourism economy, and healthy islands provide sustainable tourism opportunities, jobs and livelihoods. Access to islands must be controlled and the introduction of predators prevented. Marine Protected Areas (MPAs) can help protect island ecosystems. South African islands and their breeding seabirds are protected in several Marine Protected Areas including Robben Island MPA, Malgas island, Marcus and , Jutten Island and Bird and St Croix Islands in the Addo Elephant National Park MPA.
Support seabirds and maintain healthy ecosystems – Fisheries resources are critical for seabird populations. Changing ocean temperatures have altered the location of fish stocks. African Penguins feed on small pelagic fish like sardines and anchovy, which have moved away from the West Coast of South Africa towards the southeast coast. As penguins have to return to their nests on islands and cannot swim for long distances, they have been unable to move with their food sources. Penguins also compete with fisheries for food resources- with populations of sardines and anchovies declining because of fishing and other pressures. Sustainable fishing practices are key to the recovery of these important fish stocks and we should always choose to eat sustainable fish (www.sassi.co.za). Fishing quotas need to be allocated in line with scientific recommendations that account for the realities of resource abundance and with consideration for the needs of the ecosystem including seabirds.
How do we learn more about Islands?
Ornithologists are scientists who study birds. South Africa’s offshore islands are key research areas for studying seabirds. Birds are tagged and monitored to determine where they forage and how far they travel from their nesting ground. Seabird populations are counted to determine whether their population numbers have increased or decreased.
Dr Azwianewi Makhado
Specialist scientist: Seabirds (DFFE)
Studied: Bachelor of Science, Honours (University of Venda), Master of Science (University of Pretoria), Doctor of Philosophy (University of Cape Town)
What is interesting about the ecosystem you are working in?
It is a dynamic ecosystem faced with lots of challenges and needs to be managed holistically. Islands are very productive with lots of marine fauna and are rich in species diversity.
What are the challenges with working in your ecosystem?
We cannot manage species in isolation but we need to apply an ecosystem approach to fisheries (EAF). This holistic approach is also known as Ecosystem-based management. Implementation of such approaches helps maintain a balance between sustainable utilisation and conservation. The balance must be struck to manage those species at risk of extinction like African penguins.
What are you working on and why is it important?
I am currently managing marine top predators research activities within the Branch: Oceans and Coasts and focusing more on research on African penguins as their populations are in dire need of protection.