NATURE is all about competition, especially if you’re an Australian giant cuttlefish.

As the mating season of the Sepia apama draws closer, the males will be sharpening their unique courting skills to attract the attention of thousands of female cuttlefish in the upper Spencer Gulf.

Australian wildlife and underwater photographer Scott Portelli, of Western Sydney, captured this image, Cuttlefish Aggregation, which shows a male courting a female, while an “entourage of suiters stay poised for an opportunity to mate with the female”.

Portelli’s photo was yesterday announced as the national winner of the Sony World Photography Awards — the world’s biggest photography competition.

Portelli said the Australian giant cuttlefish aggregation was one of “nature’s great events”.

“Thousands of cuttlefish congregate in the shallow waters around the Spencer Gulf in South Australia, to mate and perpetuate the species,” he said.

“The cuttlefish, like alien beings, display an array of patterns, textures and colours to indicate their intentions. A visual delight and a rare glimpse of nature in all its glory.”

The mating season, which starts in late April or early May, sees thousands of giant cuttlefish make their way back to Point Lowly, near Whyalla, to breed.

Giant cuttlefish numbers in the northern Spencer Gulf rose 128 per cent in 2015 to 130,771, up from 57,317 in 2014 and 13,492 in 2013.

Despite being colourblind, giant cuttlefish use neurally controlled cells under their skin to change colours and patterns in a fraction of a second. They can even adjust their reflectivity.

Tony Bramley, of Whyalla Diving Services, said SA’s giant cuttlefish were “truly unique”.

“Every year they come back to the same place to breed in very large numbers, that happens nowhere else in Australia,” he said.

“You can’t experience what you get here in Whyalla anywhere else on the planet.”

Portelli’s winning image will be part of the 2016 Sony World Photography Awards exhibition at Somerset House in London from April 22 to May 8

To find out more about the awards, visit worldphoto.org