Cape town: The Department of Forestry, Fisheries and the Environment (DFFE) continues to probe the recent sardine mortality event, despite the absence of new mass-mortality incidents since Sunday, 16 August 2026. The department's ongoing investigations suggest that the acute phase of the event may have subsided, but efforts to monitor and test the situation are still underway.

According to South African Government News Agency, the department revealed that around 75 sardines have been subjected to testing for pilchard herpesvirus (PHV). Initial analyses conducted by the South African Institute for Aquatic Biodiversity and Rhodes University found PHV genetic material in 15 of the examined specimens. Notably, 10 fish from the mortality event exhibited consistently high viral levels, while the remaining five, though caught alive, displayed varying viral concentrations.

The genetic sequence of the virus shows a 99.7% match to an Australian PHV gene. In addition, approximately 60 more samples have been processed for PHV screening, with preliminary results indicating high viral levels in about half of these. Confirmatory testing is ongoing, and further pathological examinations on another 40 samples aim to identify signs of gill inflammation and damage linked to active PHV disease.

Investigations have discounted harmful algae as the primary cause, as paralytic shellfish toxins were not detected, and domoic acid and yessotoxin were only found at low levels. Analysis of stomach contents and gill materials also revealed no harmful algae in densities likely to cause such mortality.

Unusually cold water and low-oxygen conditions were noted along sections of the West Coast, yet these conditions were similar to those recorded during a recent pelagic recruitment survey, which did not report any sardine deaths. While low oxygen is a periodic occurrence on the West Coast, it has not previously resulted in sardine mortality of this magnitude.

The department suggests that the restriction of mortality to sardines makes a general environmental cause less likely, although environmental factors cannot yet be ruled out as contributing stressors. The evidence increasingly points to PHV as the primary explanation, yet its causal role will only be confirmed once pathological and broader surveillance results are available.

The department assures that PHV is a fish virus that poses no known risk to human health. There is no evidence indicating that it can infect humans or render commercially caught or canned sardine products unsafe for consumption.

In response, a high-level task team composed of DFFE, affected municipalities, management authorities, the fishing industry, and other stakeholders has convened to devise a coordinated response plan. This plan encompasses expanded surveillance and testing, guidance on disposing of dead fish, public health communication, and evaluating the potential impact on the sardine resource. The public is advised not to collect, consume, or feed dead or dying sardines to pets. Further updates will be provided as confirmed results become available.