Durban – A large number of sharks went on a 15-minute sardine feeding frenzy in Port St Johns on the Wild Coast in the Eastern Cape on Monday.
In a video circulating on social media footage taken from inside a boat shows part of the natural event.
A man is heard saying in the video: “Look at the madness here. There are sharks as far as you can see. Another one jumped into the boat(sardine)… A shark just hit the boat, this is crazy guys…absolutely crazy all around us…hundreds of sharks.”
Speaking to The Mercury on Tuesday, South African Association for Marine Biological Research(SAAMBR) scientist, Dr Ryan Daly, who specialises in marine protected areas, fish and sharks, said what happened in Port St Johns was quite unique.
Explaining the events that led to the frenzied feeding, Daly said there was a build up that started towards the end of last week.
“There was a big shoal of sardines, a big biomass, just out of Port St Johns and it seemed like the sardines were trying to come up the coast but there was a touch of really warm and clean water that pushed down and seemed to stop their migration.”
Daly said the big shoal stuck around in one place between Brazen Head and Mpande just south of Port St Johns. There were not many dolphins around.
He further explained that normally sharks rely on dolphins to drive bait balls, which are a roughly spherical dense school of fish, for them to feed.
Days prior to the feeding frenzy, Daly said there were mainly sharks and the sardines were in good water with lots of visibility. He said the sharks seemed like they were slowly cruising through the sardines.
The scientist, who has projects studying all the sharks related to sardine run along the coast, said it all came to a head on Monday.
“The sardines were pushed in shore and the visibility dropped a little bit and it seemed to lead to a critical moment where the sharks just started eating.”
“It was basically a high concentration of sharks following this big mass of sardines and the way that they feed is just to lunge at the sardines because they obviously small bait fish and the sharks need to eat them. There was just really high activity trying to feed on these sardines.”
Daly said the boats in the video drove in the middle of that and the sharks bumped the boat because they were trying to feed on the sardines.
“There were a lot of tourism related boats and they were all trying to see this because the big shoal of sardines was spotted from an aeroplane previously so everybody knew that they were there. Guys from Mdumbi and Port St Johns all went down to see the activity and it was incredible but it [the feeding frenzy] only lasted about 15 minutes.”
While there were mainly dusky sharks, Dally said it was possible that there were also other sharks like blacktips, bronze whalers and spinners, which had been seen days prior in the area.
Daly added that every year during the sardine run, the sardines spread out along the coast and there is no concentration of sharks.
“The concentration of sharks in KZN can sometimes be high but it's important to remember that sharks are only tuned into sardines. During this time the only thing a shark wants to eat is a sardine, they are not going to bite people or eat anything else because this time of the year means sardine feast. They love them.”
He said it was great to see this natural event.
“The footage yesterday[Monday] was quite a unique event to see it all like that and great for tourism. A lot of guys got to see that natural phenomenon and hopefully it will be a great sardine season in KZN going forward.”