By Lehlohonolo Lehana.
The Department of Forestry, Fisheries and the Environment (DFFE) confirmed the presence of Pilchard Herpes Virus (PHV) in sardines sampled during an investigation into a recent mortality event on the West Coast.
PHV has not previously been reported in South Africa, with DFFE saying there is no evidence that PHV infects people or other animals.
Tests conducted on sardines collected off Saldanha Bay, the Cape Canyon and Gansbaai found no paralytic toxins associated with a harmful algal bloom in Saldanha Bay.
Two other algal toxins, domoic acid and yessotoxin, were detected at low levels. The highest levels were found in an apparently healthy comparison sample collected from St Helena Bay.
No other toxins included in the screening were detected.
The department said the findings indicate that the toxins tested for were unlikely to have been the primary cause of the sardine deaths. However, harmful algae or other environmental conditions cannot be entirely ruled out as factors that may have placed additional stress on the fish.
The DFFE has convened an urgent briefing with small pelagic fishing industry stakeholders. A task team involving the department, fishing industry and other relevant stakeholders will also be established to formulate a coordinated response plan for PHV-associated sardine mortality in South African waters.
Its immediate responsibility will be to develop a coordinated response to PHV-associated sardine mortality in South African waters while scientists continue disease, pathology and environmental investigations.
Surveillance is also being expanded along the West, South and East coasts through an inter-agency effort, giving researchers a broader picture of whether the virus or unusual sardine mortality is appearing elsewhere.
The department’s routine hydroacoustic biomass survey is expected to provide the first opportunity to assess what effect, if any, the mortality event has had on South Africa’s wider sardine population.