No one has seen a certain species of sea snake in more than 15 years, prompting concerns that they have gone extinct. So imagine the surprise of researchers when they spotted a pair of these elusive sea snakes off the coast of Western Australia. The Australian short nosed sea snake (Aipysurus apraefrontalis) was officially listed as Critically Endangered back in 2010, but these aquatic creatures mysteriously disappeared from their natural habitats at Ashmore Reef in the Timor Sea sometime between 1998 and 2002. Given the complete dearth of sightings since that time, conservationists feared that they were permanently gone; the recent sighting shows they're still around.
The discovery of the aquatic snakes was confirmed after a Western Australia Parks and Wildlife Officer, Grant Griffin, sent photos of a pair of snakes taken on Ningaloo Reef to the ARC Centre of Excellence for Coral Reef Studies at James Cook University. The results of the subsequent analysis now appear in the latest edition of Biological Conservation.
Excitingly, the pair of snakes were courting, which suggests they're members of a breeding population. These creatures are classified as marine hydrophiines, meaning they're true sea snakes; they live exclusively in the water, are predatory, and give live-birth to offspring.
In yet more good news, the researchers made another unexpected discovery when they found a significant population of the rare leaf-scaled sea snake (Aipysurus foliosquama) living in the seagrass beds of Shark Bay. The snakes were spotted about 1700km south of the snakes' only known habitat on Ashmore Reef.
"This discovery is really exciting, we get another chance to protect these two endemic Western Australian sea snake species," noted study lead author Blanche D'Anastasi in a press statement. "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 researchers aren't entirely sure why sea snake populations are on the decline, but trawling may have something to do with it. As the researchers write in their study:
Most sea snakes were collected from demersal prawn trawl by-catch surveys, indicating that these species are vulnerable to demersal trawl gear. Nonetheless, the disappearance of these two species from Ashmore Reef (which coincided with extirpations of at least three other sea snake species) could not be attributed to trawling and remain unexplained.
Consequently, conservationists will need to identify the main threats to these two species if effective conservation strategies are to be implemented.
Read the entire study at Biological Conservation: "New range and habitat records for threatened Australian sea snakes raise challenges for conservation".