A fundraising effort for a man whose boat was found empty and motoring in circles in Brisbane’s Moreton Bay has raised over $30,000 in less than a day.

Fisherman Trent Riley posted two videos on social media showing calm waters two hours before he went missing on Wednesday.

The 26-year-old’s small aluminium boat was found off Mud Island, near the Port of Brisbane, at about 3.30pm.

A GoFundMe page set up to help his family “continue the search for Trent” and cover expenses has raised more than $30,000 of a $40,000 goal since it was posted on Saturday.

“Any support is greatly appreciated and will help keep Trent’s family focusing on their main goal – bringing Trent home,” it says.

Calm conditions

Queensland Police Acting Inspector Mark Mooney said Mr Riley posted two videos on Instagram at 1.27pm which showed calm conditions on the bay.

“That’s the last we heard of him, of his posting or interaction,” he told reporters on Thursday.

Insp Mooney said the boat was not damaged, indicating there had not been any collision, but one of the 26-year-old’s three fishing rods was missing.

He said a dry bag Mr Riley would have taken with him if he had “voluntarily” got into the water was still in his boat.

“We’re not totally aware at this stage how he’s fallen out of the boat,” Insp Mooney said.

Water Police, Volunteer Marine Rescue, helicopters and volunteer coastguard have been involved in the search.

At the time he went missing Mr Riley was wearing a long-sleeved grey fishing shirt, black jeans, black shoes and a bucket hat.

He is Caucasian, about 183cm tall, with a proportionate build and brown hair.

-AAP