A crown of thorns plague is eating its way through the Great Barrier Reef, almost wiping out at least one reef between Cooktown and Cairns.
It is the fourth major outbreak since 1960s and is yet to reach its peak.
Starting in Lizard Island in 2010, starfish numbers are believed to have reached at least one million.
Professor Morgan Pratchett from the Coral Reef Studies research centre at James Cook University says the plague will expand towards Townsville and Mackay in the coming years.
A series of cyclones and increased port development have already resulted in low coral cover, compounding the affects of the outbreak.
"It couldn't have come at a worse time," Professor Pratchett told AAP.
"We're starting from a very low base, it will cause an almost complete loss of coral on some reefs."
Emily Reef, between Cairns and Cooktown, was saved from the brink when almost 11,000 crown of thorns starfish were removed.
According to Professor Pratchett there is only one boat, with a crew of 12, removing the starfish from the reef.
Armed with a new single-shot poison, they are making quicker progress than previous years and can kill up to 50 of the native species a day.
"Each starfish killed will save ten square metres of coral each year," Professor Pratchett said.
"There needs to be a significant increase of investment if we're going to put a dent in the population."
Although scientists are yet to pinpoint the cause of outbreaks, it is widely accepted that plagues are boosted because of a decrease in predators and an increase in fertiliser run-off.
© AAP 2017