In 2000 Seacare Inc. in conjunction
with CSIRO, received funding from the Fisheries ActionProgram,
a branch of the National Heritage Trust to conduct a survey for the distribution
of the introduced Japanese seaweed Undaria pinnatifida in Tasmania.
In recognition of the likely possible future impact of the long spined sea urchin Centrostephanus rodgersii on Tasmania's marine biota, the survey has since been extended to include this organism.
Surveys for subtidal marine organisms can be very expensive. Three qualified dive personnel are needed for each search team and the area each team can search per day is minimal compared to the length of the Tasmanian coastline. View video of Undaria. Involving people who normally spend time in this environment can make searches for subtidal marine organisms a lot more cost effective. One group who spends a lot of time in the subtidal marine environment are the Tasmanian abalone divers. They have been approached and have agreed to be active participants in this survey. Other groups such as sport divers are also being asked to participate in this survey.
In Tasmania, the Japanese seaweed Undaria pinnatifida was first identified in 1988 in the Orford-Triabunna area. Since then it has expanded its range and is now found on Tasmania's east coast from Bicheno to Conningham. It has also been found in Port Phillip Bay, Victoria. The alga, in many areas, forms very dense stands to the exclusion of other marine biota and must be impacting in as yet undetermined ways. In New Zealand, the Government is treating the threat of this alga that seriously, it has spent millions of dollars trying to eradicate it from the southern islands.
Undaria is a seasonal alga. Between February and May there is very little evidence of the alga as it has a microscopic stage. From September to December the alga is in full bloom with plants up to 3m in length. Surveys must take place over this period to optimise the chances of finding the alga if present.
Results from the Japanese seaweed survey will, when combined with previous
surveys reveal information regarding the means and rate of distribution.
This information is valuable in developing management plans to limit further
spread of this and other invasive marine organisms.
The Japanese seaweed Undaria pinnatifida may be distinguished from native algae by the midrib in the middle of the lamina, the 'see through' lamina and the sporophyll on the stem.
Sightings of Undaria outside of the current shown range or queries should be sent to CRIMP (Dr. Chad Hewitt, Centre of Reseach into Introduced Marine Pests, CSIRO) after February 2002.
Copyright © SeaCare Inc. 2002