By Lehlohonolo Lehana.
@GettyImages.
Department of Forestry, Fisheries and the Environment (DFFE) has confirmed that large numbers of dead white mussel, whelks and other shellfish were washed out only at St Helena Bay and Elandsbaai on the West Coast.
In a statement on Sunday, the department, said that the washed out remained confined to those two areas.
Red tides are algal blooms; that is, accumulations of large amounts of phytoplankton (single-cell algae) that are common during summer and autumn along the West Coast.
Red tides also cause oxygen depletion, which harms marine life and can lead to mass mortality.
According to the department, observations by Fisheries Control Officers (FCOs) and satellite imagery show visible red tides stretching from Elandsbaai northwards for about 100km to beyond the Olifants River Estuary.
While no fish or shellfish mortalities have been reported in these newly visible red-tide areas, the risk of toxicity remains high.
The DFFE has reiterated its warning that all shellfish – whether washed ashore, collected from rocks or harvested subtidally – should not be eaten, as paralytic shellfish poisoning toxins pose a serious health risk.
Satellite imagery and public reports have also confirmed a bioluminescent red tide in Walker Bay near Hermanus, producing bright flashes of light at night.
Although no associated fish or shellfish deaths have been recorded there, the department has again urged the public not to collect or consume shellfish from affected areas.
Further east, the DFFE reported a mass fish mortality in the Hartenbos Estuary in Mossel Bay, which it stressed is not linked to a red tide.
The department said it will continue to monitor the situation with respect to the extent of the “red tide” and resultant mass mortalities on the West Coast.