Public warnings would be communicated at affected water bodies as soon as test resullts are confirmed.

A red tide is threatening the Garden Route coastal area in the Western Cape.

The red tide is already visible from the Tsitsikamma National Park, heading past the coastal area of Knysna.

South African National Parks spokesperson Nandi Mgwadlamba confirmed the fears of those concerned about the tide and the effect it may have on the sea life, George Herald reported.

“The South African Environmental Observation Network and the Institute for Coastal and Marine Research, Nelson Mandela Metropolitan University sampled several red tide blooms in Algoa Bay and St Francis Bay on 10 December and it has made a return to our shores,” she said.

The public is advised not to eat seafood harvested during a red tide, like crayfish and shellfish, as it can lead to paralytic shellfish poisoning and death.

According to a marine and coastal management guideline from the Department of Environmental Affairs, a red tide is an algal bloom.

Phytoplankton are microscopic, single-celled organisms that float in the sea and are able to photosynthesise and form the basis of food chains in the oceans.

There are three types of red tide organisms – dinoflagellates, diatoms and ciliates.

Dinoflagellates usually lie dormant on the seabed until they are lifted to the surface during upwelling where the ideal conditions of high temperature and light trigger their germination.

Paralytic shellfish poisoning (PSP), which produces toxins that disrupt normal nerve functions, can be associated closely with dinoflagellates.

Symptoms of PSP appear between one and five hours after eating contaminated seafood.

According to Mgwadlamba, sea conditions are currently optimal for bloom formation with surface temperatures at about 22°C and cold (<12°C) nutrient-rich bottom water.

“SANParks teams and partners are still taking water samples to get it to laboratories for testing. Last year professor Brian Allanson was instrumental in analysing data from the samples, conducting microscopic tests gratis in the Knysna estuary,” she added.

Mgwadlamba said public warnings would be communicated at affected water bodies as soon as results of these tests are confirmed.

– Caxton News Service