An image that looks more like the night sky than the Great Barrier Reef has won a museum photographer one of the nation's highest photographic awards as it captures a rare insight into the underwater world.

Queensland Museum photographer Gary Cranitch recently took out gold in the Nature category at the Australian Institute of Professional Photography (AIPP) awards.

The image captures a split-second moment of coral spawning on the Great Barrier Reef near Heron Island off the central Queensland coast.

"Imagine looking at the stars in a night sky but in fact you're looking at an ocean in the middle of the night," Mr Cranitch said.

"It's filled with coral spawn — pink flecks — and it's like watching a massive star show.

Gary Cranitch says the world of underwater photography can be quiet. ( ABC Radio Brisbane: Jessica Hinchliffe )

"It's seeing another world in a very simple photo with three tones in it — black, pink and blue."

He took the image while shooting as part of the Great Barrier Reef Foundation's study into restoring coral reefs through larval seeding, similar to IVF.

Floating in the ocean at 1am in the morning

Mr Cranitch was sitting in the water for more than three hours to capture the unique image.

"Spawning happens once a year in spring and you usually try for three to four days to capture it," he said.

"I had almost given up as it was about 1am in the morning and I thought I would take off my tank and put on a snorkel.

"I got back in the water and within five minutes I was engulfed in coral spawn and then it was gone again."

A 360 image of the pristine coral reef, showing the first signs of stress at Heron Island. ( Supplied: Gary Cranitch )

He said his aim was to capture a picture that told the full story of "total inundation and being totally surrounded" by the reef.

"I sat like a human bait waiting for it happen and the spawn came and went quickly," Mr Cranitch said.

"I shot about six to seven frames and that was that, the run of coral spawn had ended."

For the love of underwater photography

The museum photographer has been shooting for more than 35 years and has a special love for underwater photography.

He said the quiet, along with the opportunity be alone with his own ideas and thoughts, made this style of photography appealing.

"Underwater photography is a different game and you have to be a good diver to begin with," he said.

One of Cranitch's favourite images, of a green sea turtle swimming solo in the ocean. ( Supplied: Gary Cranitch )

"You have to come up with something that creates that beautiful feeling of colour, movement and life underwater.

"The ocean continues to shift and move, and you see new things every time you get in the ocean so it's like a fresh start every time you go back in."

Clothing is optional

Mr Cranitch said packing for trips could be tough, with different equipment needed to capture the underwater space.

"Airlines always cringe when they see me approach the check-in counter with all my boxes," he said.

"I always say clothes are an optional extra, I manage to fit a few clothes in but it's mostly my gear.

"I sometimes get a bit smelly towards the end of it but I just jump in the water and tidy up a bit."

Using digital cameras, Mr Cranitch puts his gear into underwater housing to allow him to shoot.

Gary Cranitch has travelled to many parts of Queensland to capture the state's creatures and landscapes. ( Supplied: Queensland Museum )

"At the end of the day, all people care about is the pictures you get, not the sunburn you get," he said.

"I keep finding ways to get in the water and I've done books on the Great Barrier Reef but now I'm trying to do things in freshwater and I'm starting a project on the wetlands along the coast."

Mr Cranitch also won a silver AIPP award with distinction for his global image of the coral reef and was one point off receiving silver for his image of a green sea turtle.