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SA’s toxic algal bloom probably driving sharks closer to Adelaide beachs, experts warn for caution

Sharks are circling nearer to SA shorelines and experts say the toxic algal bloom may be to blame, issuing a blunt warning.

Man bitten by shark at Port Noarlunga (7NEWS)

Experts say the state’s toxic algal bloom is probably to blame for an increased presence of sharks closer to South Australian shorelines, as a shark measuring up to 4m was spotted at Sellicks on Friday.

Hackham man Richard Vinall was taken to hospital on Thursday morning with serious injuries after a shark attack beachside of the reef near Port Noarlanga jetty. Locals said it was considered a spot where sharks were not usually seen.

South Australian marine conservation expert Dr Mike Bossley said it was possible the algal bloom could have driven the shark to Port Noarlunga.

“Sharks can swim long, long distances, very quickly,” he said. “It’s not very far from where the algal bloom is known to be, down at the bottom of the Fleurieu.

“It’s possible that it was impacted down there and then swam up.”

He has heard increased reports of sharks and stingrays – both from the same family of marine animals – swimming in shallow water in South Australia, and it was “certainly possible” this was a result of the huge algal bloom.

Richard Vinall from Hackham was bitten by a shark at Port Noarlunga. Picture: Facebook
Richard Vinall from Hackham was bitten by a shark at Port Noarlunga. Picture: Facebook
Emergency response after the shark attack at Port Noarlunga on Thursday. Picture: Jeff Anderson / First on Scene Media
Emergency response after the shark attack at Port Noarlunga on Thursday. Picture: Jeff Anderson / First on Scene Media

Since February, millions of fish across more than 200 species have died because of the phenomenon, which was described by not-for-profit OzFish SA as a “toxic blanket” smothering marine life.

Mr Bossley said he would “certainly be cautious about going swimming” near places where the algal bloom was known to be, including the bottom of the Fleurieu Peninsula and parts of the Yorke Peninsula, but added he was “not in a position to offer advice”.

“It’s really distressing that it’s going on, and I feel terrible for the poor guy that got bitten at Port Noarlunga,” he said. “I’ve been in there hundreds of times; it’s a very popular spot.”

Estuarine ecologist Faith Coleman said sharks in South Australia were unwell and dying, “most likely as a result of the algal bloom”, while she had multiple theories about why the bloom could be driving sharks closer to the shore.

“The algal bloom is causing damage to the sharks’ gills, and that causes a lack of oxygen,” she said. “Any animal when exposed to a lack of oxygen often gets neurological issues … so that may be one theory.

“They’re tired, they’re not getting a lot of oxygen, they want somewhere to rest, which might be why they’re coming into shore.”

Police and surf rescue search the area for a shark after a man swimming was attacked at Port Noarlunga Beach on Thursday. Picture: Mark Brake
Police and surf rescue search the area for a shark after a man swimming was attacked at Port Noarlunga Beach on Thursday. Picture: Mark Brake
Police and surf rescue search the area for a shark after a man swimming was attacked at Port Noarlunga Beach on Thursday. Picture: Mark Brake
Police and surf rescue search the area for a shark after a man swimming was attacked at Port Noarlunga Beach on Thursday. Picture: Mark Brake

A state government spokeswoman said there was no scientific evidence before the government to indicate the algal bloom might make shark attacks more likely.

On Friday, Shark Watch SA posted to social media a photo of a three-to-four-metre great white shark near the shore at Sellicks Beach on Friday, 25 minutes south of Port Noarlunga.

Originally published as SA’s toxic algal bloom probably driving sharks closer to Adelaide beachs, experts warn for caution

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Original URL: https://www.weeklytimesnow.com.au/news/south-australia/sas-toxic-algal-bloom-probably-driving-sharks-closer-to-adelaide-beachs-experts-warn-for-caution/news-story/8d425dca89787392682d253b5975084a