The red tide – and all the worries over its toxicity and the much-feared paralytic shellfish poisoning it can cause – has arrived at Kenton-on-Sea.
The red tide – and all the worries over its toxicity and the much-feared paralytic shellfish poisoning it can cause – has arrived at Kenton-on-Sea.
However, it's safe to swim there, say local experts. The red tide started in early January following the announcement of the presence of possibly harmful phytoplankton collected from the Knysna Estuary.
At the time the low numbers were thought unlikely to start a bloom, but by 19 January there had been sporadic sightings of red bands in the water ranging from St Francis to the Knysna Heads.
By this stage the South African National Parks Board, the Department of Agriculture, Forestries and Fisheries, and municipalities were releasing multiple warnings as the bloom became more evident.
Red tides are caused by a build-up of certain types of algae in sea water which cause it turn a reddish-brown colour.
These in turn can result in the build up of toxins in shellfish that, when consumed by humans, can cause an array of affects.
Ailments range from dizziness, and headaches to extreme diarrhoea and even paralysis and death in extreme cases, although this is not common.
However, while shellfish should be avoided as a precaution, it's still safe to swim, Professor Peter Britz of the Rhodes Ichthyology department told Grocott's Mail on Friday 31 January.
Britz said that the latest tests results have shown that this particular algal bloom is producing a substance called yessotoxin.
Yessotoxin is not poisonous to humans, he says, although lab tests have shown it to produce reactions in mice.
“It is safe to swim in the sea and eat fish and do all the normal things,” Britz said, “although as a precaution experts are advising people to refrain from eating filter feeders such as oysters and mussels.”
He confirms that there have been fish kills as a result of the red tide but this is as a result of the algae creating a lack of oxygen, rather than the fish being poisoned by it.
With reports over the past few weeks of red tide between Port Alfred and Knysna, it has now also reached Kenton-on-Sea.
Beachgoers there say it has reached the stage where the waves on the beach are entirely red and visibility in the water is extremely poor.
Those looking to witness something unusual may be interested in the multiple reports and pictures of the algal blooms creating a phosphorescent effect at night causing the waves to glow in the dark.
These have been reported in Port Elizabeth and Jeffrey's Bay.
