Sea snakes make record-setting deep dives
Sea snakes, best known from shallow tropical waters, have been recorded swimming at 250 meters in the deep-sea 'twilight zone,' smashing the previous diving record of 133 meters held by sea snakes.
Sea snakes, best known from shallow tropical waters, have been recorded swimming at 250 metres in the deep-sea 'twilight zone', smashing the previous diving record of 133 metres held by sea snakes.
Footage of a sea snake swimming at 245 metres deep, and another sea snake at 239 metres has been provided to University of Adelaide researchers by INPEX Australia, an exploration and production company operating in the Browse Basin off the Kimberley coast of Australia. Both snakes appeared to belong to the same species.
Sea snakes are found in tropical waters of the Indian and Pacific Oceans and are typically associated with shallow water habitats like coral reefs and river estuaries.
"Sea snakes were thought to only dive between a maximum of 50 to 100 metres because they need to regularly swim to the sea surface to breathe air, so we were very surprised to find them so deep," says Dr Jenna Crowe-Riddell, lead author of the study and recent PhD graduate at the University of Adelaide's School of Biological Sciences.
Oceanic depths between 200 and 1000 metres encompass the mesopelagic zone, sometimes called the 'twilight zone' because only a small amount of light reaches that depth.
"We have known for a long time that sea snakes can cope with diving sickness known as 'the bends' using gas exchange through their skin," says Dr Crowe-Riddell. "But I never suspected that this ability allows sea snakes to dive to deep-sea habitats."
These record-setting dives raise new questions about the ecology and biology of sea snakes.
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