UPDATE: 19/2/17

Shark attack victim Glenn Dickson has had his left leg amputated and remains in a critical but stable condition in Cairns Hospital.

His friends have launched a crowdfunding campaign to help him and his family during his recovery over coming months.

You can donate to the campaign, which has already raised over $15,000, by clicking here.

EARLIER:

The remarkable quick-thinking of his spear fishing mates might just have saved Glenn Dickson's life.

The 25-year-old, who lives at South Mission Beach with his young family, is recovering in Cairns Hospital after a shark mauled his legs shortly after he jumped into the pristine waters off Eva Island, located close to Hinchinbrook Island, at around 10.30am this morning.

A Queensland Ambulance spokesman said Mr Dickson was bitten multiple times in his left femur and calf, suffering severe blood loss and losing consciousness. They believe he was attacked by either a bull or tiger shark.

His mates rushed him to shore in their boat and he was treated by paramedics on a jetty. A rescue helicopter transported him to Cairns Hospital, where he underwent surgery late this afternoon.

"The friends have immediately pulled him out of the water and applied emergency first aid," the spokesman told ABC News.

"They put a tourniquet up high and tight on his femur and stopped the subsequent bleeding which was quite significant."

The waters off Eva Island are renowned for good fishing, with several fishing tours running in the area.