Cape Town – There have been no fresh sardine mortalities for more than a week, the Department of Forestry, Fisheries and the Environment has revealed.
“No new mass-mortality incidents have been reported since Sunday, 16 August 2026, suggesting that the acute phase of the event may have eased,” the department said on Sunday, 23 August 2026.
However, the department said it continues to investigate and monitor the recent sardine mortality event.
“Approximately 75 sardines have been included in the PHV testing programme to date,” the department said.
“Initial testing by the South African Institute for Aquatic Biodiversity and Rhodes University detected pilchard herpesvirus (PHV) genetic material in all 15 fish examined.
“Of these, 10 fish collected from the mortality event showed consistently high viral levels.
“Viral levels varied among the five fish that were caught alive and appeared healthy at the time of collection.”
The department revealed that the viral sequence was a 99.7% match to an Australian PHV gene.
The department said it has processed approximately 60 additional samples for PHV screening.
Preliminary results available for about half of these indicate high PHV levels.
“Confirmatory testing is continuing, while pathological examinations of a further 40 samples are under way to determine whether the fish show the characteristic gill inflammation and damage associated with active PHV disease,” the department said.
“Investigations into other possible causes have not found evidence that harmful algae were the primary cause.
“Paralytic shellfish toxins were not detected, while domoic acid and yessotoxin occurred only at low levels, with the highest concentrations in an apparently healthy comparison sample.”
The department said the examination of stomach contents and material rinsed from the gills also found no harmful algae at densities likely to have caused the mortality.
“Unusually cold water and low-oxygen conditions were observed along parts of the West Coast,” said the department.
“However, these conditions were broadly similar to those recorded during the recent pelagic recruitment survey before the event, when no dead or dying sardines were observed.”
Low oxygen also occurs periodically on the West Coast without previously causing sardine mortality on this scale.
The department explained that the apparent restriction of the mortality to sardines makes a general environmental cause less likely, although environmental conditions cannot yet be excluded as contributing stressors.
“Taken together, the evidence increasingly points to PHV as the leading explanation, but its causal role will only be confirmed once the pathological and wider surveillance results are available,” stated the department.
PHV is a fish virus and poses no known risk to human health.
There is no evidence that it can infect or cause disease in people.
The department said its detection does not, by itself, mean that healthy sardines caught commercially or canned sardine products are unsafe to eat.
A high-level task team comprising the department, affected municipalities, management authorities, the fishing industry and other relevant stakeholders held its first meeting and agreed on a coordinated response plan.
This includes expanded surveillance and testing, clearer guidance on the disposal of dead fish, public-health communication and an assessment of the possible impact on the sardine resource.
“The public should continue not to collect, consume or feed dead or dying sardines to pets,” the department warned.
