Rare sea snakes feared extinct discovered off the coast of Western Australia

  • Scientists have discovered several live leaf-scaled and short-nosed sea snakes on reefs off the coast of Western Australia, according to a study.
  • The team even identified a pair of courting short-nosed sea snakes on Ningaloo Reef, which suggests that they are members of a breeding population, scientists say.
  • This study provides the “first unequivocal records” of the leaf-scaled and short-nosed sea snake in coastal waters of Western Australia, scientists say.

Between 1998 and 2002, two critically endangered species of sea snakes — the leaf-scaled sea snake (Aipysurus foliosquama) and the short-nosed sea snake (Aipysurus apraefrontalis) — disappeared from their only known habitat in the Ashmore and Hibernia Reefs in Timor Sea, off the coast of north-western Australia. Not having spotted the sea snakes for more than 15 years on these reefs, many conservationists feared that the snakes were probably extinct.

Now, scientists from James Cook University (JCU) and Curtin University in Australia have discovered several live leaf-scaled and short-nosed sea snakes on reefs off the coast of Western Australia, according to a study published in the journal Biological Conservation.

“This discovery is really exciting, we get another chance to protect these two endemic Western Australian sea snake species,” lead author Blanche D’Anastasi from the ARC Centre of Excellence for Coral Reef Studies at JCU, said in a statement.

Critically endangered leaf scaled sea snake. Photo by Blanche D’Anastasi
Critically endangered leaf scaled sea snake. Photo by Blanche D’Anastasi

Inspired by anecdotal reports of the two sea snake species in coastal waters of Western Australia, the team launched surveys to look for the elusive sea snakes. Soon, they found some individuals that were “alive and healthy”.

The team discovered several live individuals of the rare leaf-scaled sea snakes in Shark Bay, 1,700 kilometers (~1,056 miles) south of their previously known natural habitat on Ashmore Reef.

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

The team also found five individuals of the short-nosed sea snake that had been captured live during trawl by-catch surveys. They even confirmed the record of a pair of courting short-nosed sea snakes on Ningaloo Reef. Grant Griggin, a Western Australia Parks and Wildlife Officer, had captured the snakes in a photograph and sent it to 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,” lead author Blanche D’Anastasi from the ARC Centre of Excellence for Coral Reef Studies at JCU, said. “What is even more exciting is that they were courting, suggesting that they are members of a breeding population.”

Courting short-nosed sea snakes photographed on Ningaloo Reef. Photo by Grant Griffin, WA Parks and Wildlife Service
Courting short-nosed sea snakes photographed on Ningaloo Reef. Photo by Grant Griffin, WA Parks and Wildlife Service

According to the team, this study provides the “first unequivocal records of live animals for A. foliosquama and A. apraefrontalis in coastal waters of WA and is the first to document that A. foliosquama occurs as far south as subtropical Shark Bay.”

While the discovery of the sea snakes is a win, scientists say that there are a number of unanswered questions. For example, over the last two decades, there have been several unexplained declines of sea snakes at several locations, including Ashmore Reef which was declared a National Nature Reserve in 1983, the authors write.

The researchers speculate that a number of threats — such as trawling, loss of habitats and prey, disease, and offshore developmental activities — could be driving the snakes’ decline.

“However, until we identify the causes of previous extirpations of Aipysurus group species, it will be challenging to implement effective conservation strategies,” the authors write.

“Thus, in addition to the need for further field surveys to accurately document the true range extents and population sizes of species, it also is critically important that targeted research be conducted to further our understanding of the biology and ecology of sea snakes, and address knowledge gaps about the key threatening processes,” they add.

A) Map showing key locations throughout the study region. Specific locations (purple dots) of survey sites are shown at B) Scott Reef; C) Ningaloo Reef and Exmouth Gulf; and D) Shark Bay. Locations of previously published records (stars) and new records from this study (filled circles) for E) Aipysurus foliosquama (green) and F) Aipysurus apraefrontalis (pink), including two WAM samples initially identified as A. pooleorum, but reassigned to A. foliosquama (circled star).  From D'Anastasi et al 2015.
A) Map showing key locations throughout the study region. Specific locations (purple dots) of survey sites are shown at B) Scott Reef; C) Ningaloo Reef and Exmouth Gulf; and D) Shark Bay. Locations of previously published records (stars) and new records from this study (filled circles) for E) Aipysurus foliosquama (green) and F) Aipysurus apraefrontalis (pink), including two WAM samples initially identified as A. pooleorum, but reassigned to A. foliosquama (circled star). From D’Anastasi et al 2015.

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