Bull sharks can make ‘friends,’ new study from Fiji’s Shark Reef Marine Reserve suggests

Charlotte EltonThe West Australian
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VideoMan attacked by shark tells his story

Bull sharks may be terrifying predators – but they can make “friends”, according to a new study.

Researchers studied 91 individual sharks over 13 years, scanning data from 3000 dives in Fiji’s Shark Reef Marine Reserve.

They found the sharks – which can grow up to 3.5 metres in length – had "preferred companionships and casual acquaintances."

"Long-term preferred companionships and strong affinity between individuals were observed throughout the study," the research, published in the Frontiers journal, reads.

By identifying sharks by permanent features such as scars, wounds, missing and/or damaged fins, scientists could watch if the same individual sharks were drawn together again and again.

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According to Dr Juerg Brunnschweiler – the independent shark researcher from Switzerland who designed the study – "companionships" formed between certain sharks.

"Some bull shark individuals seem to prefer long-term companions and avoid others," he told the Guardian.

Camera IconCameron Wrathall survived being attacked by a bull shark in the Swan River. Credit: 7NEWS

In February, Bicton father Cameron Wrathall was mauled by a bull shark in the Swan River.

Mr Wrathall was just 100m from shore near Blackwall Reach when he was attacked by the three metre shark, who broke his hip and ripped through his groin and buttock. He spent two days unconscious in hospital as trauma surgeons fought to save him.

“The shark hit me really hard, it's the biggest impact I've ever felt of something hitting me,” he said.

In November last year, Broome man Charles Cernobori was fatally mauled by a bull shark while swimming off Cable Beach.

The only other recorded fatal bull shark attack in WA was in the Swan River in the 1920s, when a young boy was killed.

Camera IconCharlie Cernobori was fatally mauled by a bull shark at Cable Beach. Credit: Unknown/Facebook

However, Dr Brunnschweiler was apprehensive about using the term "friends."

"Friendship is a relationship of mutual affection between people. Not animals," he said.

"It would be anthropomorphic to speak of friendships here."

The study used "baited dives," which attract massive numbers of sharks. Researchers suggested that future research should include a separate "control" site, where they could watch to see if the same dynamics play out.

"If we have two individuals that are observed together at the SRMR more or less regularly, and if they also show up together at another site with the same or similar probability than at the SRMR, then this would make our results much more robust," Dr Brunnschweiler said.

"And would indicate that there is indeed some level of sociality in this species."

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