A new study published by Adelaide University researchers has revealed that several endangered Aipysurus sea snakes comprise distinct and locally adapted populations that require separate conservation management to ensure their survival.
Researchers analysed thousands of genome-wide markers alongside detailed measurements of body shape and colouration from five widespread Aipysurus lineages.
They discovered that coastal and offshore-reef populations are genetically distinct, have been separated for up to 950,000 years, and show consistent differences in body size, vertebral counts, and colour pattern.
“These lineages have followed strikingly similar evolutionary trajectories,” said lead author James Nankivell, from Adelaide University’s School of Biological Sciences.
“Coastal sea snakes tend to be longer-bodied and paler, while offshore populations show adaptations suited to complex coral reef habitats. These differences reflect long-term isolation and local adaptation.”
The findings, which were published in BMC Ecology and Evolution, have immediate conservation relevance.
Offshore populations of Aipysurus apraefrontalis, A. foliosquama, A. duboisii, and A. fuscus inhabit small, fragmented reef systems in the Timor Sea – several of which have experienced dramatic, unexplained population crashes over the past two decades. Three of these species are listed as Endangered or Critically Endangered under the Australian EPBC Act.
The authors recommend that coastal and offshore groups of these species be formally recognised as Evolutionarily Significant Units (ESUs) – a conservation category identifying populations with unique genetic and ecological characteristics that should be managed separately.
“Recognising these ESUs ensures we maintain the full breadth of evolutionary potential in these snakes,” said senior author Associate Professor Kate Sanders, also from Adelaide University.
“It also allows managers to better target protection for the most vulnerable populations, particularly those on remote reefs where declines have already occurred.”
The study underscores the need for renewed field surveys in the Timor Sea and improved assessment of coastal threats, including trawl-fishery bycatch and habitat alteration linked to expanding coastal infrastructure.
This research provides an essential foundation for designing marine protected area networks that safeguard the unique biodiversity and adaptive capacity of Australia’s sea snakes.