The man, aged in his 30s, was attacked at Byron Bay, 36 kilometers (22 miles) north of Ballina, where a 25-year-old man sustained minor leg injuries while surfing with friends on Oct. 12, a police statement said.
On Sept. 26, a 17-year-old surfer required stiches to close a leg wound after he was bitten by a shark off Ballina, 600 kilometers (350 miles) north of Sydney.
A 41-year-old Japanese surfer was killed by a shark off Ballina last year.
A surfer who administered first aid at the scene, Geoffrey Knapp, said the victim had been lying on his board when the shark attacked. The fiberglass board took the brunt of the bite, Knapp said.
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The victim "clearly saw the tail and he got the impression that the shark was trying to knock him off his surfboard and roll him over," Knapp told Australian Broadcasting Corp.
Hundreds of protesters gathered at Ballina today to demonstrate against government plans to place anti-shark nets along beaches around Ballina.
Police said beaches around Byron Bay would remain closed for 24 hours after the attack.