A short-nosed sea snake species, which was previously thought to be extinct, has been spotted in Australia, the journal Biological Conservation has reported. Now, scientists are planning to protect the snake species, including Aipysurus apraefrontalis.

The journal also reported that researchers also found some other similar species. The IUCN Red List of Threatened Species suggested that the newly spotted snake’s population has declined more than 90% in last 15 years. In 1990s, Aipysurus apraefrontalis was one of the most common sea snake species, but since 2000, no sighting was reported, it added.

“We were blown away, these potentially extinct snakes were there in plain sight, living on one of Australia’s natural icons, Ningaloo Reef. What is even more exciting is that they were courting, suggesting that they are members of a breeding population”, Blanche D’Anastas, lead researcher of the new discovery, said in a statement.

Scientists said they are now planning how to protect the Western Australian sea snake species that lived on Ashmore Reef in the Timor Sea. They will monitor the snake and examine its biology and threats that they can face, said D’Anastas.

Scientists didn’t reveal why snake populations are dwindling in marine parks. Dr. Vimoksalehi Lukoschek, a researcher from the Centre of Excellence for Coral Reef Studies to Eurekalert, said most of the newly discovered snakes were found in prawn trawl. It is necessary to understand why the number of sea snakes has been decreasing.

Researchers published the discovery of living Aipysurus apraefrontalis snakes, along with another thought-to-be-extinct snake species, in the journal Biological Conservation on Monday. The short-nosed sea snake has been listed as critically endangered since it disappeared from its only known habitat, the Ashmore Reef in the Timor Sea.

It's the first time the snakes have been spotted alive and healthy since disappearing from their only known habitat on Ashmore Reef in the Timor Sea more than fifteen years ago.

"This discovery is really exciting, we get another chance to protect these two endemic Western Australian sea snake species," says study lead author Blanche D'Anastasi from the ARC Centre of Excellence for Coral Reef Studies at JCU.

"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".

The discovery of the critically endangered short nose sea snake was confirmed after a Western Australia Parks and Wildlife Officer, Grant Griffin, sent a photo of a pair of snakes taken on Ningaloo Reef to Ms D'Anastasi for identification.

"We were blown away, these potentially extinct snakes were there in plain sight, living on one of Australia's natural icons, Ningaloo Reef," says Ms D'Anastasi.

"What is even more exciting is that they were courting, suggesting that they are members of a breeding population."

The researchers also made another unexpected discovery, uncovering a significant population of the rare leaf scaled sea snake in the lush seagrass beds of Shark Bay.

The discovery was made 1700 kilometres south of the snakes only known habitat on Ashmore Reef.

"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," says Ms D'Anastasi.

Both leaf scaled and short nosed sea snakes are listed as Critically Endangered under Australia's threatened species legislation, which means they have special protection.

Despite the good news of the find, sea snake numbers have been declining in several marine parks, and scientists are at a loss to explain why.

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

"But the disappearance of sea snakes from Ashmore Reef, could not be attributed to trawling and remains unexplained.