The Department of Forestry, Fisheries and the Environment (DFFE) says it is continuing to investigate the recent sardine mortality event, although no new mass-mortality incidents have been reported since Sunday, 16 August 2026.
The department said the absence of further large-scale incidents suggests that the acute phase of the event may have eased, but monitoring and testing are continuing.
In a statement issued on Sunday, the department reported that approximately 75 sardines have been included in the pilchard herpesvirus (PHV) testing programme to date.
Initial testing by the South African Institute for Aquatic Biodiversity and Rhodes University detected PHV genetic material in 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 said.
The viral sequence showed a 99.7% match to an Australian PHV gene.
DFFE has also processed approximately 60 additional samples for PHV screening, with preliminary results available for about half of these samples indicate high PHV levels.
The department said 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.
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. Examination of stomach contents and material rinsed from the gills also found no harmful algae at densities likely to have caused the mortality,” the department said.
Unusually cold water and low-oxygen conditions were observed along parts of the West Coast. However, the department said these conditions were broadly similar to those recorded during the recent pelagic recruitment survey prior to the event, when no dead or dying sardines were observed.
The department noted that low oxygen also occurs periodically on the West Coast without previously causing sardine mortality on this scale.
“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,” the department said.
The department reiterated that 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. Its detection does not, by itself, mean that healthy sardines caught commercially or canned sardine products are unsafe to eat.”
Coordinated response plan
Meanwhile, a high-level task team comprising DFFE, affected municipalities, management authorities, the fishing industry and other relevant stakeholders has held its first meeting and agreed on a coordinated response plan.
The plan 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 has been urged not to collect, consume or feed dead or dying sardines to pets.
The department will provide further updates as confirmed results become available. – SAnews.gov.za
