Scientists from James Cook University have spotted two endangered species of sea snakes for the first time in years - and previously thought to be extinct - off the coast of Western Australia. The findings were confirmed by photos released from Grant Griffin, a Western Australia Parks and Wildlife officer. Since vanishing from the Ashmore Reef in the Timor Sea more than 15 years ago, the finding marks the first time that the species have been seen alive.

"This discovery is really exciting, we get another chance to protect these two endemic Western Australian sea snake species," Blanche D'Anastasi, lead author of the study, said in a press release. "But in order to succeed in protecting them, we will need to monitor populations as well as undertake research into understanding their biology and the threats they face."

"We were blown away, these potentially extinct snakes were there in plain sight, living on one of Australia's natural icons, Ningaloo Reef," D'Anastasi said. "What is even more exciting is that they were courting, suggesting that they are members of a breeding population."

The findings were made approximately 1,700 kilometres south of Ashmore Reef, the only known habitat of the species. In addition, the researchers found a large population of the rare leaf scaled sea snake in Shark Bay, where they thrived in the numerous seabeds.

"We had thought that this species of sea snake was only found on tropical coral reefs. Finding them in seagrass beds at Shark Bay was a real surprise," D'Anastasi said.

Despite the promise of the findings, sea snake populations continue to decline in numerous marine parks and researchers are still unable to understand the reasons behind the decline.

"Many of the snakes in this study were collected from prawn trawl by-catch surveys, indicating that these species are vulnerable to trawling," said Vimoksalehi Lukoschek from the Centre of Excellence for Coral Reef Studies.

The data will be published in the February 2016 issue of Biological Conservation.