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Case closed: Aussie marine biologist solves Dendy Beach “bloody legs” mystery

Marine biologists around the world have solved the mystery of Sam Kanizay’s bloody legs.

On Saturday, Kanizay went for a soak in the waters of Dendy Street Beach.

By Monday, he was international news. CNN said that Sam had been playing soccer. Fake news. We know it was footy.

When Sam emerged from the waters his legs were bleeding profusely. After his father, Jarrod, was unsuccessful in stopping the bleeding, Sam was taken to a nearby hospital.

But the hospital seemed puzzled by the injuries too. Why wouldn’t the bleeding stop? What did this? Theories ranging from sea lice to mantis rays to tiny fish were tossed about. No one knew for sure.

Jarrod went back to Dendy Street Beach on Sunday night looking for answers. He caught a sample of the critters and they ended up in the hands of Genefor Walker-Smith, a marine biologist from Museums Victoria.

Walker-Smith examined the sample and deduced the culprit to be lysianassid amphipods, a type of scavenging crustacean.

“It’s possible the amphipods contained an anti-coagulant, which would account for the inability to stop the flowing blood and that the very cold water may be the reason Sam didn’t feel the bites,” Museums Victoria wrote in a Facebook post. “The amphipods have no venomous properties and will not cause lasting damage.”

Although the media has been referring to the amphipods as “sea lice”, Museums Victoria says that term is usually used for isopods, a different group of crustaceans. A more accurate nickname for amphipods is “sea fleas”. “The creatures are naturally-occurring scavengers, which commonly bite but do not usually cause these injuries,” Museums Victoria wrote.

Marine biologist, Dr Victoria Metcalf, who is currently working as the National Coordinator of the Participatory Science Platform in New Zealand shared her insights into this strange phenomenon with Techly.

She was clear that sea fleas are unlikely to launch full-scale attacks on humans, but she did offer some advice – “Keep moving, keeping away from dead fish etc in the water and swimming at day rather than evening or nighttime all help. There’s no need for any mass scale panic here. This is a highly uncommon incident and other users of the same water space have reported no issues.”

When asked whether the transition between winter and spring might influence the activity of the sea fleas, Metcalf pointed to light and food availability being the biggest influences. However, she did mention an interesting study which showed the influence of climate change on sea flea behaviour – apparently drastic changes in climate can result in a population explosion due to increased male attractiveness. Wowee.

Back at Brighton, the “Icebergers”, a group who regularly swim at Dendy Beach in winter seem unfazed by the possibility of crustaceans eating them alive.

“We’re probably too gritty and tough and old for those creatures to worry about,” an Iceberger named Paul Duckett told The Age. Duckett called the incident “bizarre” and noted that he and his group had seen sharks and stingrays on their swims. One Iceberger even stepped on a stingray barb once. These Icebergers are hard. Sea fleas don’t scare them, OK?

So how about Sam?

At the time of writing, Sam remains in Dandenong Hospital. According to The Age, doctors have taken a biopsy as a precaution, but expect him to be fine.

“He’s certainly on the mend; we hope that he makes a full recovery,” Jarrod told The Washington Post. “He might come home with some scars. We’re hoping not.”

Jarrod added that Sam, a true Aussie battler, will eventually return to the water.

About the author

Stefan is an Adelaide-based freelance writer. In his spare time, he plays tennis badly, collects vinyl and brushes up on his Mandarin. Follow Stefan on Twitter

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