Red tide: Do not to eat the washed-out marine animals

Red tide in Lamberts Bay. Pic: Candice Mostert

Red tide in Lamberts Bay. Pic: Candice Mostert

Published Feb 13, 2024


Cape Town - A warning of another red tide has gone out to caution residents not to eat washed-out marine animals.

This came after a large number of dead marine animals washed up on beaches along the West Coast due to the annual red tide.

The Department of Forestry, Fisheries, and the Environment (DFFE) said the mortalities, including from eating prawns, crabs, cuttlefish, sea worms and shark rays, were first reported from the Berg River mouth area close to Velddrif.

The department said: “The appearance of washed-up lobsters carries significant health risks, rendering them unsuitable for consumption.”

Uncertainty surrounding their time of death, coupled with potential contamination by algal toxins, posed dangers to human health.

“Ingestion of these toxins can lead to severe adverse reactions and even fatalities.”

Peter Mbelengwa, DFFE spokesperson, said the department, in collaboration with various national and local authorities, had responded to the walkouts through the West Coast Rock Lobster Walkout Contingency Plan.

He said the plan involved collecting live lobsters, relocating them to areas with normal oxygen levels, and ensuring the safe disposal of deceased lobsters.

“Simultaneously, scientists closely monitor the red tide, document the species washed ashore, and conduct analyses, including size and sex composition.

“Large-scale lobster walkouts have profound consequences for both the marine ecosystem and local economies.

“Recent research by the Department’s Crustacean Research team uncovered substantial reductions in lobster densities following walkouts of 550 metric tons in 2022 and 100 metric tons in 2023, particularly impacting Elands Bay,” said Mbelengwa.

Red tides are algal blooms which are accumulations of large amounts of phytoplankton (single-cell algae).

“These blooms may be harmful due to their toxicity and/or due to their drastically reducing oxygen levels in the sea as they begin to decay. These, in turn, often result in mass mortalities of marine organisms. Possibly the best-known impact is on the West Coast rock lobster (Jasus lalandii), locally called kreef. Mass mortalities of this species are called ‘walkouts’,” said Mbelengwa.

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