Cape town: As a wide-ranging investigation continues, the Department of Forestry, Fisheries and the Environment (DFFE) is urging the public not to collect or consume dead fish found on beaches, the department said. This advisory comes as no dead or dying sardines have been reported to the DFFE since Thursday, 6 August, suggesting that the recent mortality event along the Western Cape coast has run its course.
According to South African Government News Agency, West Coast canneries continue to accept healthy sardines caught north of St Helena Bay, while some factories in affected areas have elected to await the Department's results before resuming operations. The cause of the sardine deaths has not yet been confirmed. A comprehensive investigation involving the department, research institutions, specialist laboratories, the fishing industry, and other collaborating scientists is ongoing.
In a statement on Sunday, the department said that samples of dead sardines have been collected from various locations including Saldanha Bay, Hout Bay, Betty's Bay, Gansbaai, and the Cape Canyon area. As a precaution, while testing continues, the public is advised against collecting or consuming dead fish found on beaches. Healthy sardines from Elands Bay and Lambert's Bay have also been gathered for comparison purposes. The South African Institute for Aquatic Biodiversity (SAIAB) and Rhodes University are conducting disease testing, while SAIAB and a specialist commercial laboratory are screening samples for marine biotoxins.
The department's scientists are examining water samples, stomach contents, and gills for evidence of harmful algae. Basic biological examinations, including measurements of size, weight, condition, and maturity, as well as macroscopic examination of the gills, have been undertaken. A harmful algal bloom caused by Alexandrium catenella was present in Saldanha Bay when the mortality began. This harmful alga has previously been linked to sardine mortalities in South Africa and remains one of the possible causes under investigation. However, it has not been detected in the water samples or sardine stomach contents examined to date, and preliminary analyses have not identified a harmful-algal cause.
Oceanographic information supplied by SAEON and the CSIR indicates enhanced upwelling, unusually cold nearshore water, and low oxygen levels in St Helena Bay before the event. A southward-moving coastal current could also have transported affected fish from the West Coast towards Cape Point and farther east. These observations provide useful context but do not establish the cause of the sardine deaths.
No wider effects on the marine ecosystem have been reported, and the department noted that sardines are an important food source for seabirds, seals, and predatory fish. The DFFE will continue to monitor any possible effects on the sardine population and its predators.
The department extended their gratitude to the fishing industry, individual fishers and vessel crews, CapMarine, BirdLife South Africa, SAIAB, Rhodes University, SAEON, the CSIR, Cape Nature, other collaborating scientists and specialist laboratories, and members of the public who supplied reports, photographs, videos, and samples. The response demonstrates the strong collaboration between government, research institutions, specialist laboratories, and the fishing industry, enabling multiple parallel lines of investigation to proceed rapidly.
Further updates will be provided once disease testing and initial biotoxin results are available, most likely early next week. These specialized analyses take time as samples must undergo several stages of preparation, testing, and verification before the results can be interpreted reliably.
