‘Pregnancy test’ to detect Great Barrier Reef scourge
Queensland scientists have developed a dipstick test that can detect crown-of-thorns starfish on coral reefs, using the same technology as home pregnancy tests.
The dipstick, designed to be used in the field, measures specific DNA the sea creatures release into the ocean.
The rapid test, developed by Australian Institute of Marine Science researchers, can detect very low numbers of the coral-eating pest, which can be difficult to spot with current survey methods.
More development of the test is needed but the big hope is it could one day be used by citizen scientists and tourism operators to feed information back to authorities about crown-of-thorns starfish infestations on the Great Barrier Reef.
AIMS biochemist Jason Doyle said he started working on the test about two years ago by investigating if medical diagnostic tools could be adapted for use in the marine environment.
Like a home pregnancy test, the CoTS dipstick reveals a positive response via the appearance of a stripe.
"The home pregnancy test is for particular hormones that get produced if a woman is pregnant," Mr Doyle said.
"The diagnostic technology of the dipstick is essentially the same. There's a target compound that, in the case of a pregnancy dipstick, is a hormone. In the case of our crown of thorns starfish dipstick, it's a piece of DNA."
An average adult crown of thorns starfish can eat up to a dinner-plate amount of coral a day and outbreaks contribute considerably to the loss of corals on the reef.
The native starfish often hide under coral plates and younger CoTS can be as small as a couple of millimetres, making it difficult for traditional surveys using boats and snorkellers, to spot the creatures and identify emerging outbreaks, when population densities are low.
Researchers successfully used the dipstick test on filtered seawater samples from Lizard Island, north of Cairns, and Elizabeth Reef, north of Mackay, finding crown of thorns DNA where other survey methods had failed to pick up any signs of the animals.
Mr Doyle said the study was the first step in developing a tool that could eventually require just a few drops of seawater to detect crown-of-thorns starfish, but more work was needed to simplify the process.
At the moment, researchers filter about two litres of seawater to concentrate DNA before using the dipstick to test for the presence of the starfish.
Eventually, they hope to be able to provide simple kits to citizen scientists and tourism operators that can be used on the reef. They could then download the information about the presence of crown-of-thorns starfish onto an app and beam that back to reef authorities.
"We see this application not to take over existing survey techniques," Mr Doyle said.
"Rather, we see it very much sitting within the early warning camp so we can raise a red flag and say: 'Maybe we should have a look at these sites and focus our resources to maximise the management outcome'."
The research, published in the journal, Environmental DNA, was funded by the National Geographic Society and the Ian Potter Foundation.
Originally published as 'Pregnancy test' to detect Reef scourge