Disappearing sea snakes surprise researchers with hidden genetic diversity
New research suggests an urgent need to find out why sea snakes are disappearing from known habitats, after it was discovered some seemingly identical sea snake populations are actually genetically distinct from each other and can’t simply repopulate if one group dies out.
Lead author, Dr Vimoksalehi Lukoschek from the ARC Centre of Excellence for Coral Reef Studies at James Cook University collected genetic samples from more than 550 sea snakes around Australia.
She said scientists were previously unaware of how genetically different sea snake populations on the Western Australian coast were from populations on reefs in the Timor Sea, Gulf of Carpentaria and the Great Barrier Reef.
“The previously unappreciated genetic distinctiveness in coastal Western Australia is critically important. It means that this region is home to genetic diversity not found elsewhere in Australia. If those populations die out, then that biodiversity and potential for adaptation is lost forever,” said Dr Lukoschek.
“Also, genetic differences of sea snakes between reefs around Australia mean that if a species disappears from a particular reef, they are unlikely to be replenished by dispersal of juveniles or adults from adjacent reefs.”
Dr Lukoschek said the sudden disappearance of sea snakes on the highly-protected Ashmore Reef in the Timor Sea remained unexplained, as were sea snake declines on protected reefs in New Caledonia and the southern Great Barrier Reef.
“We observed none of the obvious threats, such as changes in the habitat or fishing, so we are left with a list of other possible causes including disease, invasive species, pollution, seismic surveys or recruitment failure.”
Dr Lukoschek said targeted research on habitat and diet requirements, reproductive biology, disease susceptibility and the impacts of man-made processes, is crucial.
“It’s important we investigate sea snakes in particular, as traditional conservation actions that focus on tackling common causes of species decline, such as habitat loss, may not optimise the conservation of genetic divergence and diversity in these vulnerable populations,” she said.
Dr Lukoschek said conservation planners should incorporate genetic information, including identifying and prioritising evolutionarily significant lineages, into their work.
“In the meantime, the findings suggest it is imperative to reduce stressors to coastal WA habitats including minimising the impacts of trawling and reducing the numerous anthropogenic impacts on the environment,” Dr Lukoschek concluded.
The paper “Congruent phylogeographic patterns in a young radiation of live-bearing marine snakes: Pleistocene vicariance and the conservation implications of cryptic genetic diversity” is published today in the journal Diversity and Distributions.