Full Breakdown
Mass Sardine Strandings on South Africa’s South Coast Linked to Pilchard Herpesvirus
9/1/2026, 8:24:33 AM
Core Event
In early August, thousands of dead sardines and pilchards washed ashore on Hobie and Pollock beaches in Gqeberha, South Africa’s south-coast city. Residents reported that the strandings continued for several days, with similar die-offs having occurred weeks earlier along the Western Cape. Scientists identified pilchard herpesvirus (PHV) in both dead and apparently healthy sardines collected from the affected areas, marking the first confirmed presence of the virus in South African waters.
Background and Emerging Threat
PHV caused two major sardine mortality events in Australia and New Zealand during the 1990s, wiping out roughly 70 % of the local stock. Genetic sequencing of South African samples showed more than 99 % similarity to the Australian strain, suggesting the virus may have been introduced from overseas. Researchers note that low sardine stocks, oxygen-depleted waters and harmful algal blooms can increase vulnerability, but government testing found no evidence of paralytic shellfish toxins and only low levels of other marine toxins, making algal poisoning an unlikely primary driver.
Official Statements & Responses
The Department of Forestry, Fisheries and the Environment (DFFE) said on August 30 that PHV remains the leading explanation for the Western Cape mortality and that a link between the Gqeberha and Western Cape events is considered likely, while also pledging to investigate other environmental factors. DFFE spokesperson Zolile Nqayi cautioned that detection of the virus does not prove it caused the deaths.
Craig Smith, senior technical specialist at WWF South Africa, said the organization is working with government and industry to respond and warned that the current wave could be followed by a more deadly second wave. An intergovernmental task team and the Small Pelagic Scientific Working Group are coordinating surveillance, testing, disposal of dead fish and impact assessments, with a meeting scheduled this week to consider additional management measures.
Impact and Concerns
Dead sardines clogged the cooling-water intake at Koeberg nuclear power station, forcing the national electricity utility to halve output at one of its two units. Sardines are a keystone species, feeding dolphins, seals, seabirds and the critically endangered African penguin; loss of the fish threatens these predators, especially the large penguin colony in Algoa Bay. Conservationist Ronelle Friend warned that uncontrolled fishing already strains penguin food supplies, and the virus could exacerbate the problem. Veteran Durban fisherman Bonny Adams noted that the 2026 sardine run was already quieter and expressed uncertainty about future catches. The scale of the mortality remains unclear, with a more comprehensive picture expected after DFFE’s annual hydroacoustic survey later in 2026.
Verbatim Quotes
- “This is the first time it has happened in South African history,” — Nadine Strydom, a professor in the zoology department at Nelson Mandela University — Nadine Strydom, professor, zoology department, Nelson Mandela University.
