Dr Teina Rongo, with an experienced crew of free divers, have collected 800 of the taramea from outside the reef since the eradication programme started in July.
Yesterday, only seven of the taramea aged at about three to four years old, were caught - a good sign of the success of the exercise.
Rarotonga is an isolated island and so relies on itself to replenish its reef.
“It can take as long as 20 years for the reef to recover to a healthy state – we know this from the taramea outbreak in the 90s,” Dr Rongo said.
“We don’t want to wait for another outbreak like that, when we started eradicating them then it was too late, they were already around the island.”
This time around the taramea were discovered early,.
The outbreak usually starts from Avatiu harbour, the leeward side of the island, towards the eastern side of Edgewater Resort.
Dr Rongo and volunteers free dived 17 to 20 metres along the reef from Arorangi back to the harbour, working against the current in order to not alert the taramea that use the water to send out signals - a lesson learnt from the eradication in the 90s.
“Back then, when we would return the next day, they had disappeared,” he said.
A humpback whale and her calf, dolphins, turtles and giant rays greeted the divers along the way, an experience that Kura Happ and Rose Winters will treasure.
The crew are almost done, the next step is to go over and moniter the areas they have covered.