Pilchard herpesvirus detected in South African sardine mortality event

Laboratory sequencing has confirmed the presence of pilchard herpesvirus (PHV) genetic material in sardines following a mass mortality event along South Africa’s West Coast. The Department of Forestry, Fisheries and the Environment (DFFE) reported that the virus was detected in both dead specimens and apparently healthy fish, suggesting that the virus alone may not be the sole cause of the deaths.

Scientists are investigating whether environmental stressors, such as low oxygen levels, unusual oceanographic conditions, or harmful algae, acted as catalysts. While trace amounts of domoic acid and yessotoxin were detected in samples from Saldanha Bay, the Cape Canyon, and Gansbaai, these toxins were found at higher levels in healthy samples, making them unlikely primary causes. This is the first time PHV has been reported in South African sardines.

There is currently no evidence that the virus infects humans or other animals, and the DFFE has stated there is no justification for suspending commercial fishing or canning operations. However, the public is warned not to collect, consume, or feed dead or dying fish to pets. An urgent task team has been established to coordinate a response, and biomass surveys will be conducted in October and November to assess the impact on the sardine population.