Invasive caulerpa, also known as killer algae, grows at speed over the seabed and smothers all sea life beneath.
This resulting carpet of caulerpa means fish, shellfish and kelp have little chance of survival. And it could put big industries such as fishing and tourism at risk.
Government officials say it can't be eradicated from our waters, but how much damage will it do?
Is there any way caulerpa can be stopped?
Sunday's Conor Whitten takes a deep dive into the issue in the report above.
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Reporter: Conor Whitten
Producer: Steve Butler
Cameras: Tory Evans, Cameron Murray, Steve Hathaway, Julian Braadtvedt, Will Green
Editor: Paul Anderson
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