NSW Department of Primary Industries (DPI) has recently detected two non-native marine seaweed pests in NSW waters for the first time, and community members have been asked to report any sightings.
The species are the red macroalga Grateloupia turuturu and Pachymeniopsis lanceolata. This is the first detection of Grateloupia turuturu in NSW waters and the first detection of Pachymeniopsis lanceolata in Australia.
Pachymeniopsis lanceolata is a large, flesh-pink to dull muddy red, sheet-like plant (50–200 cm long, 30––50 broad) with a very small attachment to the rocks and a broadly forked blade which gets battered over time. It gets sunburnt and goes yellow as it gets older. It is about as thick as a shirt cuff, and feels velvety and slippery. It grows, in winter and spring, on the tops and edges of rocks at the low tide mark, usually in bays.
Grateloupia turuturu is a long, narrow, large and wavy, crimson red seaweed, (up to 150 cm long, and 20 cm broad) with a tiny attachment and stalk. As a rule it is found slightly deeper in the water, so it doesn’t get sunburnt. It is a little thicker than a piece of paper, and is very slippery, but crisp. It forms a skirt round the bases of rocks and boulders in bays and will grow on ropes, pylons and seagrass fronds, in winter and spring.
The species were detected in Botany Bay by Dr Stephen Skinner from the National Herbarium of NSW, Royal Botanic Garden Sydney. Samples were then able to be analysed by DPI staff at Elizabeth Macarthur Agricultural Institute to confirm the species identification.
Both species are native to parts of Asia and are known to behave as weed species elsewhere. As well as being confused with each other due to the similarities in their physical appearance, they are both known to be very difficult to identify in the field.
Both species can out-compete many native seaweeds within the low intertidal and shallow subtidal zones due to their large size and ability to reproduce quickly.
Melissa Walker, DPI Team Leader Aquatic Biosecurity, said water users are encouraged to notify NSW DPI should they suspect any further populations of these species in new locations.
“Water users are advised to not disturb these species if moving around in the locations they are known to occur,” said Ms Walker.
“If they suspect further populations of these species in new locations, they are asked to notify DPI by calling the 24 hour hotline, on 1800 675 888.”
Water users are also reminded to ensure boats and aquatic gear and equipment are cleaned before moving into a new location, to avoid the unwanted spread of non-native marine pest species.