A Yorke Peninsula woman is recovering from an unusual and aggressive eagle ray attack after a 15cm barb pierced her arm, barely missing an artery.

Pam Bennett was part of a group investigating the effects of an algae bloom on the South Australian coast when the incident occurred.

Minutes after entering the water, she was struck from behind. 

“Suddenly felt this… what felt like a dog bite,” Bennett said.

“At that moment, there probably wasn’t excruciating pain. The pain comes after.”

The attack resulted in a 15-centimetre stingray barb becoming lodged in her arm, requiring emergency treatment at the Royal Adelaide Hospital. 

Bennett said she was fine.

“I’ve got a sore arm that’s all,” she said.

A marine biologist who witnessed the attack has told 9News it is unusual and aggressive behaviour, and believes it could be linked to the algae bloom.

“One [eagle ray] attacked Pam and one which actually lashed out at me, fortunately missed,” Dr Mike Bossley said. 

“She was bleeding quite profusely and had to get her to medical attention.”

Bossley believes the uncharacteristic aggression may be linked to the algae bloom affecting parts of the South Australian coast. 

He explained that warmer-than-usual waters are fueling the bloom, which can coat the gills of marine life, potentially depriving them of oxygen.

 “I’ve been snorkelling and diving for 50 years and never seen anything remotely like this,” he said. 

The attack comes a day after a great white shark was found dead on Henley Beach.

The algae bloom and its potential effects on marine life are under investigation by the Department of Primary Industries. 

According to Bossley, a natural event may be needed to resolve the issue. 

“The only thing that will help is if we get a decent storm coming in from the south-west, which will break up the bloom and disperse it,” he said.