Warning for people living in Cape Town
Laboratory tests have confirmed the presence of pilchard herpesvirus in sardines affected by a mass mortality event along the Western Cape coastline.
The Department of Forestry, Fisheries and the Environment (DFFE) confirmed that laboratory sequencing detected genetic material of the pilchard herpesvirus (PHV) in the sampled sardines.
However, the department has cautioned that scientists have not yet determined whether the virus alone caused the mass deaths.
Although the virus may not be transmissible to animals or humans, a public warning has been issued advising residents not to collect or eat the fish.
This latest development comes as photographs and reports circulated over the weekend showing dead sardines along the beaches of Milnerton, Sunset Beach, and Lagoon Beach.
Dead fish were also reported at Milnerton Lagoon on Friday.
These reports are significant because the DFFE had previously stated that it had received no notifications of dead or dying sardines after the 6th of August, suggesting that the mortality may have concluded by then.
The official investigation has covered a large portion of the Western Cape coastline. The DFFE had earlier confirmed that samples of dead sardines were collected from Saldanha Bay, Hout Bay, Betty’s Bay, Gansbaai, and the Cape Canyon area.
Dead and dying sardines were also observed floating at sea up to eight nautical miles offshore near Hout Bay, with large numbers of dead fish washing ashore at Melkbosstrand.
The department reported that PHV had been detected in both the dead sardines and, at lower levels, in some apparently healthy sardines collected from the West Coast.
“This suggests that the presence of the virus alone may not be sufficient to cause mass mortality,” the department said.
Scientists are currently investigating whether another environmental stressor may have triggered or worsened the deaths.
Possible factors being examined include harmful algae, low oxygen levels, and unusual oceanographic conditions.
Earlier information provided to the investigation by the South African Environmental Observation Network and the Council for Scientific and Industrial Research indicated that there was enhanced upwelling, unusually cold nearshore water, and low oxygen levels in St. Helena Bay prior to the mortality event.
The virus cannot survive in other hosts
“We want to assure residents that this phenomenon has nothing to do with the Milnerton Lagoon,” said the City’s Deputy Mayor and Mayoral Committee Member for Spatial Planning and Environment, Eddie Andrews.
Andrews clarified that sardines do not inhabit the Milnerton Lagoon or the estuary; they are oceanic fish.
He said the DFFE is currently investigating the cause of sardine mortality along the West Coast and will keep residents updated on its findings.
The City of Cape Town confirmed sightings of sardine mortalities at various locations along Cape Town’s west coast. These deaths are believed to be linked to a larger fish die-off, as previously explained.
“We would like to remind residents not to allow their pets to consume marine life or unidentified objects found along the shoreline in general, and to not move or dispose of the fish yourself, should you observe any,” said Andrews.
In an interview with Cape Talk, DFFE Senior Marine Scientist Janet Coetzee explained that there are over 100 species of herpes virus, with a few occurring in humans.
However, Coetzee confirmed that the PHV is specific to this species of sardine and cannot survive in any other host species, whether human or animal.
“We are not worried that people are going to get herpes from eating infected fish. The concern is rather that we don’t know how long these fish have been dead,” said Coetzee.
She explained that the fish could be decaying and harbouring other organisms and bacteria that could be harmful. She said that it remains unclear when the virus entered South Africa’s oceans.
Loading ...