Overview
This seaweed readily invades new places and is now found in Australia, both in New South Wales and South Australia. If it arrived in New Zealand it could cause serious problems to our marine ecosystem.

It is found at depths of 3-35 m on rock, sand or mud in sheltered or moderately wave-exposed areas. It smothers other plant life in the area it invades and reduces the habitat available for fish and other animals.

Mode of distribution
Caulerpa is used in the marine aquarium trade. Its most likely path of introduction to New Zealand would be by accident (eg, from the dumping of a hobbyist's aquarium into the sea) or possibly from the outflow of a marine pet supplier's holding tanks.

Description
Size: Fronds between 3-15 cm long in shallower lighter conditions and 40-60 cm in deeper water. Stolon diameter of 1.5-1.8 mm but less than 2.8 mm.
Shape: Horizontal tubular stolon with fronds protruding at right angles. The fronds are flat.
Colour: Green

Key features
The flattened fronds are an important feature to look for. Another important characteristic of caulerpa is the fact that the fronds get narrower as they near the top of the frond.

Action plan
Caulerpa action plan August 2001 (PDF 348KB).

(You'll need Adobe Acrobat Reader to read the PDF files; it's available to download for free. It may take a while to download.)