ASFB Home > 2003 > Biological Invasions: Consequences for Parasites, Pathogens, Emerging Diseases, and Fisheries in the Marine Environment.

Invasions of temperate Australian waters by the tropical seaweed Caulerpa taxifolia.

Dr Bob Creese and Mr Bill Talbot

NSW Fisheries – Port Stephens Fisheries Centre, Private Bag 1, Nelson Bay 2315 Australia
Email: Bill.Talbot@fisheries.nsw.gov.au

Caulerpa taxifolia is a seaweed native to tropical regions throughout the world, including tropical and subtropical parts of Australia, with its southern limit at Moreton Bay in Queensland. It has been widely used in the marine aquarium trade. The ‘aquarium strains' can invade cool temperate waters, and Caulerpa taxifolia has become established in several countries and areas where it is not naturally found. Since March 2000 Caulerpa taxifolia has been located in eight in NSW estuaries and has covered an area of approximately 340 ha. This has raised significant concerns as Caulerpa taxifolia has the potential to grow rapidly and smother native seagrass. Evidence from the Mediterranean indicates that it may degrade marine ecosystems and threaten biodiversity.

The NSW Government has created an aquatic pest management group with a major focus on a control program for Caulerpa taxifolia. The program includes declaring the weed noxious, removing it from the aquarium trade, controlling infestations in priority areas and eradicating them where possible, educating the public and restricting the use of fishing gear to help stop the weed spreading.

NSW Fisheries researchers have tested a variety of control methods, including handpicking, dredging, smothering and applying salt. For most situations salt treatment appears to be the most efficient control method. Research work has focussed on developing effective salt dosage rates and application methods, and the impact of salt on native seagrasses and benthic infauna.

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