Lifesavers herded the shark out to sea before reopening Cottesloe, North Cottesloe and Leighton beaches.

Manager of operations for Surf Lifesaving WA Chris Peck said hundreds of people were warned from the water after the Cottesloe shark sighting. Sirens and flags were used to alert swimmers to the emergency.

There are an average of 15 shark attacks a year in Australian waters, one of the highest rates in the world. But Taronga Zoo in Sydney, which keeps a file on attacks, says there have only been 60 fatalities in the past 50 years.

HUNDREDS of swimmers were warned from the water and three of Perth’s most popular beaches closed for almost an hour yesterday after a 2m-long shark was seen near the shore.

Lifesavers herded the shark out to sea before reopening Cottesloe, North Cottesloe and Leighton beaches.

The incident completed a weekend of drama on the nation’s beaches, following an attack at Shelley Beach in northern NSW on Saturday, when a shark pulled a 26-year-old man from a boogie board after biting him on the lower leg.

The man was airlifted to Lismore Hospital. He was conscious and talking during the flight, but was kept in overnight hospital for observation.

Manager of operations for Surf Lifesaving WA Chris Peck said hundreds of people were warned from the water after the Cottesloe shark sighting. Sirens and flags were used to alert swimmers to the emergency.

Lifesavers in boats, using the engines to scare the shark, herded it more than a kilometre offshore. It was last seen heading south.

Mr Peck urged swimmers to follow lifesavers’ instructions whenever a shark was spotted.

In another incident a 25-year-old man was airlifted to Sydney’s Royal Prince Alfred Hospital from Maroubra Beach on Saturday after he swam into a patch of bluebottles.

He went into shock from the pain of the stings and was treated in the emergency department but later released.

This weekend’s attacks follow an abalone diver’s miraculous escape from the jaws of a 4m great white two weeks ago on the NSW south coast.

There are an average of 15 shark attacks a year in Australian waters, one of the highest rates in the world. But Taronga Zoo in Sydney, which keeps a file on attacks, says there have only been 60 fatalities in the past 50 years.