Four years after Mick Fanning fought off a shark on live TV while competing in South Africa, the World Surf Tour's safety protocol was activated on Easter Monday during the Rip Curl Pro.

It proved a false alarm, with a large clump of seaweed the culprit.

The scare comes a year after the Margaret River Pro was also called off because of two nearby non-fatal shark attacks.

"Jack and I saw a big shadow and started to paddle in not knowing what it could be," Wright said of their round-two heat.

"Jack was waving at the skis and they came over to us and we jumped on the back and went to see what it was.

"We got over to the shadow and it turns out it was a massive clump of seaweed, but it was good that we took the precaution and the safety protocols worked well."

Wright won the elimination heat and Freestone also progressed to the round of 32, while compatriot Harrison Mann was third and is out of the competition.

After three lay days, the Rip Curl Pro finally resumed at the back-up Winkipop break next to Bells Beach.

Seven-time world champion Stephanie Gilmore opened her Bells Beach title defence with a win in round one.

Gilmore trailed fellow Australians Kobie Enright and Bronte Macaulay, but the four-time Rip Curl Pro champion had the two highest wave scores of the heat, a 7.67 and a 7.83, to snare the lead.

That gave Gilmore a winning heat score of 15.50, with Enright second on 11.77 and Macaulay forced into the elimination round.

Macaulay then won her round-two heat to stay alive.

"I get frustrated at Winki because I tend to pick bad waves," Gilmore said.

"I look at waves and think they won't be good and paddle past them then the ones I choose are worse then I end up in a bad headspace."

Gilmore and compatriot Kobie Enright, who gained entry by winning last week's trials event, advanced to a showdown in the last 16.

Three-time world champion Carissa Moore, fellow Hawaiian Coco Ho, teenage American phenomenon Caroline Marks and Australian Nikki van Dijk also progressed from their heats in round one.

American star Courtney Conlogue, a two-time winner at Bells Beach, finished runner-up to Macaulay in their round-two heat to progress..

Competition finally resumed on Easter Monday in one metre-plus conditions, with the men and women completing their opening two rounds.

The three remaining round-one men's heats started the Monday schedule, with Hawaiian two-time world champion John John Florence among the winners.

Australian Associated Press