August 21, 2019 08:10:33
Tropical sea creatures are a rarity at Christopher Dornan’s local beach, given it is more than 1,500 kilometres from anywhere remotely tropical.
- A tropical sea snake has been spotted at the bottom of WA near the town of Esperance
- One expert suggests warming ocean temperatures may cause sea snake distributions to expand globally
- The yellow-bellied sea snake has also been found in the chilly waters of Tasmania and in the Atlantic Ocean
Yet an expert has confirmed the reptile spotted by the Esperance teacher on the chilly shores of Alexander Bay was indeed a yellow-bellied sea snake — marking the first verified record of a living sea snake in the area.
While reptile enthusiast Brian Bush — a man with no formal qualifications, but whose passion for reptiles has seen several snakes named in his honour — said he saw three sea snakes washed ashore during the decade he spent in the region, all of them were dead.
But sea snake research scientist Blanche D’Anastasi of James Cook University said it could be a sign of things to come, as warming ocean temperatures advance sea snake distributions globally.
Mr Dornan ventured to Alexander Bay, about 100km east of Esperance on Western Australia’s southern coast, earlier this month with his wife and a friend, who quickly spotted the sea snake.
While they initially thought it was a moray eel, he said the tail looked decidedly like a sea snake.
“We didn’t know whether it was cold and had come out of the water to get warm or was stuck up on the high-tide mark,” Mr Dornan said.
“We poked it a little bit to see if it was OK, and it sort of slithered a bit, but it didn’t seem able to move towards the ocean.”
While he said they debated over moving it back into the sea, they were wary of its famously venomous bite.
Last year an English traveller working on a trawler boat in the Gulf of Carpentaria died after being bitten by a sea snake.
Mr Dornan said he was also surprised to see the creature near such temperate waters, with oceans in the region dropping to as low as 13 degrees Celsius at this time of year.
“I’d never heard of a sea snake being down here before. It’s very odd,” he said.
“Both my wife and my friend, we’ve lived up north and they grew up there in the Pilbara and the Kimberley.
“They were used to seeing sea snakes in the water and a couple of times on the beach and they always looked pretty feisty.
“But this one looked a little bit more sedate; it didn’t look quite as happy.”
Surfing its way down the coast
Ms D’Anastasi said she had never heard of a sea snake sighting near Esperance before, even though WA was a global hotspot for sea snake diversity, with nine endemic species.
She said the most similar incident on record was of an olive sea snake sighting 580km away at Albany in 2013.
“I don’t have any records of sea snakes in Esperance,” she said.
“For a little sea snake to make it all the way down the south coast and then trek along the line to Esperance is really interesting.”
Mr Bush said he had never encountered a sea snake that made it to the area alive.
“I was on the Esperance sand plains for 10 years and probably in that time three [dead ones] turned up,” he said.
Ms D’Anastasi believes the creature had surfed the Leeuwin current down the coast of WA, but was most likely in poor condition when it washed ashore.
“Occasionally if they’re unwell they’ll strand themselves because they’re afraid of drowning,” she said.
“It’s possible that this little snake floated down in a current and then has been unwell and has stranded in Esperance.”
Ms D’Anastasi said once ashore, sea snakes were at greatest risk of predation from birds and dehydration.
She recommended that anyone who came across a stranded sea snake should place a bowl of fresh water nearby to ward off the latter.
But given the animals were highly venomous, she urged the public to be cautious and call a wildlife carer as soon as possible.
Sea snake sighting in Tasmania
Ms D’Anastasi’s tips could be worth jotting down, as warming oceans are set to expand the distribution of the world’s 70 species of sea snakes.
She said the yellow-bellied sea snake had the largest distribution of any sea snake and was notorious for surfing oceanic currents, with one even found alive in Tasmania.
During the El Nino weather conditions in 2015, Ms D’Anastasi said sea snakes were spotted in the North Pacific for the first time in 20 to 30 years.
She urged anyone who found a sea snake to record it on the Australian Sea Snakes Facebook page, where the information would be submitted to national records databases and become publicly available.
“As the climate warms we will see sea snakes spread further south.
“There is some early evidence that sea snakes are occurring in cold, temperate waters with increasing frequency.”
Although that could see the deadly creature in Esperance waters more often, Mr Dornan said it would be unlikely to deter the locals.
“A few of the guys at school surf, they were just laughing, saying it’s another reason to stay out of the water,” he said.
“But none of them seem to — they’re all back in there.”