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Stop The Spread Of Invasive Seaweed: Putting The Cap On Caulerpa

Why is Caulerpa a problem?

Caulerpa taxifolia is an invasive marine seaweed that has been found in coastal waters of NSW, including Lake Conjola, Burrill Lake, Sydney Harbour, Narrawallee Inlet, Port Hacking, Botany Bay, Pittwater and Lake Macquarie. It is a threat to the environment because it overruns native seagrasses, can dramatically alter marine ecosystems and is difficult to eradicate. Caulerpa threatens coastal ecosystems in NSW may alter marine habitats and biodiversity.

Caulerpa is introduced from small fragments accidentally transported by boat owners and other water users. Such fragments can survive for days in damp conditions amongst anchor rope, fishing gear or diving equipment.

How to recognise Caulerpa taxifolia?

Caulerpa taxifolia is a bright green seaweed with 'palm-like' fronds that can be 5 - 65 cm in length. It typically covers the seabed in dense growth, and will spread fast growing horizontal 'runners' into adjacent areas.

Caulerpa taxifolia

Description of caulerpa taxifolia

What can you do to help us control the spread of this marine pest?

If possible, avoid boating in shallow weedy areas, and particularly near Caulerpa taxifolia outbreaks. Propellers can cut the plant into small fragments that can drift away and grow into new plants.
Obey any vessel exclusion zones or fishing closures in your area, and if in doubt seek advice from your local NSW Maritime or Department of Primary Industries (DPI) Office (see link to office listings below).
Inspect all equipment, including
- anchors, ropes and chains for pieces of Caulerpa before leaving an area.
- fishing equipment such as fishing lines, nets and traps before and after use.
- diving equipment such as wetsuits, bags and other gear before and after use.
- trailers, propellers and engine intakes when retrieving your vessel from the water.
Use dedicated 'wash-down' facilities where available, ensuring that your vessel is thoroughly free of all matter before leaving the area.
Collect any fragments of Caulerpa that you may have accidentally picked up. Seal the pieces in a plastic bag and dispose of them in a bin where they cannot re-enter the waterway.
Contact your local NSW Maritime or DPI office if you think you have found Caulerpa taxifolia in a new area.

What can you do to help us control the spread of this marine pest?

If possible, avoid boating in shallow weedy areas, and particularly near Caulerpa taxifolia outbreaks. Propellers can cut the plant into small fragments that can drift away and grow into new plants.
Obey any vessel exclusion zones or fishing closures in your area, and if in doubt seek advice from your local NSW Maritime or DPI Office.
Inspect anchors, ropes and chains for pieces of Caulerpa before leaving an area.
Inspect fishing equipment such as fishing lines, nets and traps before and after use.
Inspect diving equipment such as wetsuits, bags and other gear before and after use.
Inspect trailers, propellers and engine intakes when retrieving your vessel from the water.
Use dedicated 'wash-down' facilities where available, ensuring that your vessel is thoroughly free of all matter before leaving the area.
Collect any fragments of Caulerpa that you may have accidentally picked up. Seal the pieces in a plastic bag and dispose of them in a bin where they cannot re-enter the waterway.
Contact your local NSW Maritime or DPI office if you think you have found Caulerpa taxifolia in a new area.

Are there ways of removing Caulerpa from NSW waterways?

DPI is currently trialing a number of methods to remove localised infestations, and covering the plants with large amounts of salt has shown initial promise. Removal by hand-picking or mechanical means is rarely effective as it is difficult to get all the plant material or avoid releasing fragments.

Where can I get further information or report possible sightings?

Further information can be obtained through the DPI fisheries website site http://www.dpi.nsw.gov.au/fisheries. If you suspect a new infestation of Caulerpa taxifolia, contact the NSW Dept of Primary Industries (DPI) Aquatic Biosecurity Unit on (02) 4982 1232 or report it on the 24hr Pests Reporting Line (02) 4916 3877 or email aquatic.pests@dpi.nsw.gov.au. Alternatively, contact your local NSW DPI Fisheries office or NSW Maritime operations centre.

FAQs

Link to Frequently Asked Questions on Caulerpa taxifolia