A Wandering Albatross on its nest on Marion Island. A Wandering Albatross on its nest on Marion Island.
Image: FILE
The situation on Marion Island was being closely monitored by overwintering field personnel who have been trained to recognise possible high pathogenicity avian influenza (HPAI) signs in birds and seals, following the confirmation of HPAI in six bird species.
The Department of Forestry, Fisheries and the Environment said among Wandering Albatrosses, chicks were mostly affected, with at least 150 of approximately 1900 chicks from the 2024 cohort having died.
Adults have been affected worst in other species including at least 80 adult Brown Skuas, and approximately 120 adult King Penguins. Smaller numbers of affected giant petrels (at least 20 Southern and four Northern) and Sooty Albatrosses (five) have been observed.
“The deaths of adult seabirds are of greater concern than chicks, because most species only start to breed at 3 to 10 years of age, and most affected species raise at most one chick per year.”
The department said the presence of HPAI (H5N1) virus on Marion Island was confirmed and samples collected between September and December 2024 were all shipped back to mainland South Africa, via the SA Agulhas II, in February 2025.
In March, Polymerase Chain Reaction (PCR) testing confirmed infection in six bird species, comprising Wandering Albatross (Diomedea exulans), King Penguin (Aptenodytes patagonicus), Brown (Subantarctic) Skua (Stercorarius antarcticus), Southern Giant Petrel (Macronectes giganteus), Northern Giant Petrel (M. halli) and Sooty Albatross (Phoebetria fusca).
“Following an initial suspected HPAI case in a Brown Skua at Marion Island (a bird showing clinical signs of HPAI infection including twitching and tremors) in mid-September 2024, more similar cases were reported in early November and mortalities in multiple species have continued into March 2025, though the overall death rate slowed significantly in January.
“The reduced mortality rate is promising, but 31 bird species breed on Marion Island and the bird species and age composition varies throughout the year, therefore it is difficult to predict how the outbreak will progress. The potential effects on marine mammals are also of concern but no increased mortality has been reported in any mammal species so far,” the department said.
The situation on Marion Island was being closely monitored by the field personnel overwintering on the island, who will continue to take all precautions to ensure they do not spread the virus.
“There are few other disease mitigation tools available in this type of situation,” the department said.
Marion Island, along with neighbouring Prince Edward Island, provides critical breeding and moulting grounds for millions of seabirds and marine mammals, including nearly half of the world's Wandering Albatrosses, hundreds of thousands of penguins, and large numbers of Southern Elephant Seals and Subantarctic and Antarctic Fur Seals. The Archipelago is located in the south western Indian Ocean, about 2000km southeast of Cape Town and halfway between Africa and Antarctica.
Cape Times