Four beaches on Australia's east coast were closed Sunday after numerous shark sightings, police said, as authorities patrolled waters off a southern island following a fatal attack on a diver a day earlier.
New South Wales police said the beaches at Ballina -- where a bodyboarder was severely injured by a shark earlier this month and a Japanese surfer was killed in February -- would be closed for 24 hours.
"About 9.30am (2330 GMT Saturday) a large shark was spotted swimming about 50 meters off Angels beach," police said in a statement, adding that there were other sightings.
"It is believed the presence of baitfish has attracted large sharks to the area."
Surf Life Saving NSW said aerial, jet ski and boat patrols were being conducted off Ballina, a popular tourist spot about 740 kilometres north of Sydney.
The sightings came a day after a scallop diver, named as Damian Johnson by the Australian Broadcasting Corporation and aged in his late 40s, was attacked by a shark off Maria Island in the southern state of Tasmania as his daughter watched.
Johnson was hauled back to the surface but did not survive.
Johnson's brother-in-law Andrew Paynter said his daughter, who is aged in her 20s, was "doing a remarkable job under... some really really trying circumstances".
"(Johnson was) just a great bloke, devoted husband, great father, just a great friend to all those who knew him," Paynter told the ABC.
Tasmanian police and fishing boats patrolled the waters off Maria Island Sunday, with people warned to stay away.
According to Sydney's Taronga Zoo Australian Shark Attack file, the last fatal shark attack in Tasmania was in 1993, when a woman was killed while scuba diving near a seal colony off the state's north coast.
While the shark's breed has not yet been determined, the mayor of nearby Glamorgan, Michael Kent, said locals had spotted a 4.5-metre (15-foot) great white in the area over the past week.
"There's been a so-called white pointer seen a couple of times over the last week out and about but (there are) not particularly a lot of sharks in and around that particular area," he told the ABC.
Experts say attacks are increasing as water sports become more popular, but fatalities remain rare.