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Several Facebook posts shared a video claiming it shows the annual sardine run along the coast of South Africa’s Eastern Cape Province. It’s wrong; Although the annual migration of silverfish currently takes place along the country’s east coast, the video on Facebook shows an algal bloom known as the red tide that has emerged in the Western Cape.
The 20-second video in the Facebook post has been shared more than 3,200 times since its publication on April 19, 2021. Recorded from a helicopter, the footage shows a dark ocean mass approaching shore.
“LARGEST SARDINE RACE IN 100 YEARS FORECAST SARDINES NOW IN EAST LONDON,” the post caption read.
Similar claims have been shared hundreds of times here and here on Facebook, but some people commenting on the post noted that the clip actually depicts the red tide and not the annual sardine race.
Red tide in False Bay
According to Stephen Lamberth, a fisheries researcher at the Department of Environment, Forestry and Fisheries (DEFF), the video was shot during a flight over the Helderberg Marine Protected Area in Strand, Cape Town, which can be viewed from the Helderberg mountains and the Lourens river estuary in the background.
“The dark reddish-brown color of the water (red tide) comes from a very dense phytoplankton bloom, mainly from the dinoflagellate Ceratium furca [a type of algae]Lamberth said. “It is not toxic but occurs at very high densities, which depletes oxygen levels at night, and when it eventually dies and disintegrates.”
Red tide is a common occurrence on the west and east coasts of South Africa, especially at this time of year, Lamberth explained, adding that there had been “localized killed fish” within days. that followed the shooting.
“Southeasterly winds cause upwelling of cold, nutrient-rich bottom waters on which phytoplankton thrive. Blooms occur in the even relatively less windy period after upwelling, ”said Lamberth.
The same video and a description of the red tide phenomenon was also shared on Facebook by Just Africa Scuba, a locally based scuba diving operator.
“The red tide is a common occurrence on the West Coast at this time of year and is caused by a specific type of plankton,” reads part of the caption of their article, published April 9, 2021.
AFP Fact Check contacted the group, who confirmed the footage showed the red tide, an annual event driven by the wind.
“All locals now know that when they see the water turn brown and smell a specific scent, it’s red tide again,” said Mari van Wyk, spokesperson for Just Africa Scuba.
Van Wyk said the footage clearly showed a red tide because the mass was too large to be a school of sardines, which also attract predators from below and above.
“With a school of sardines, you will see birds flying and catching fish along with other marine mammals feasting on sardines,” van Wyk said in an email to AFP Fact Check. None of this feeding activity is evident in the video.
A day after their Facebook post, Just Africa Scuba explained on their website why the ocean was turning red.
Kegan Matthys, owner of Fishing Republic, a fishing shop in Strand, agrees – he told AFP Fact Check that they have been “fighting” against the red tide for a month and that he still sees more. traces.
“I actually fished this morning (April 29), and there is still a red tide in the water. The wind changed direction and pushed everything back into the bay towards us, so there is always a red tide, certainly not sardines, ”said Matthys.
He added that the confusion may stem from the fact that people have seen more sardines in the area than in previous years.
“It happened just before the tide came in properly. So the sardines were thick here before they died, and as soon as the red tide started it seemed like the baitfish was gone, not completely, but I think that’s where the confusion arose, ”said Matthys.
As the Africa News Agency reports, a red tide on the west coast in January 2021 saw several marine species washed up dead on the beach.
Then, on March 25, 2021, the DEFF issued a statement on “Inflows and Mortalities of Fish and Shellfish on the West Coast of South Africa”.
Another reference to the red tide was made in a congratulatory message to open water swimmer Howard Warrington, who completed 22 km on April 9, 2021, “in difficult conditions with the red tide, heavy swells and heavy water. agitated ”.
Each year, as the weather cools in South Africa, vast schools of sardines move north along the country’s east coast in South Africa. Known as the sardine run, this enormous marine migration creates a feeding frenzy, producing spectacular images and stimulating local tourism operators.
The first sardine school of 2021 was spotted in the Eastern Cape in mid-April 2021, and according to this article, local nets were hoping for a big bounty to match the days gone by.