Biosecurity 2.1
Development of gene probes for introduced marine pest species (Musculista senhousia, Corbula gibba, Sabella spallanzanii).
| ID Number | Project Number | Manager | Start Date | End Date | Total Project Funds ($) |
| SVE-4036 | RD04/0197 | Westphalen, Grant | 10-Jun-2005 | 30-Jun-2006 | 227,273 |
Executive Summary
There is an identified need for marine pest monitoring to detect new incursions of species already present in Australia, and to detect exotic species not yet recorded in Australia. Current methods of identification rely on specialist taxonomic skills. These skills are not always readily available, and routine surveillance may generate more samples than specialist laboratories can handle.
DNA techniques allow rapid and definitive identification of target taxa. They are useful as an adjunct to traditional morphological identification, as well as a tool for rapid and high-throughput monitoring. One of the potential strengths of this technology is that it allows identification of multiple taxa in a single sample. However, there are only a small number of target taxa for which DNA tests have been developed. A concerted effort has been made to develop DNA based assays for a number of priority marine pests.
In this study, real-time PCR tests have been designed for three taxa of introduced marine pests- Sabella spallanzanii, Corbula gibba and Musculista senhousia. These tests have been demonstrated to be specific for the target taxa.
This study demonstrates that the real-time PCR tests can be used to quantify the organisms in phytoplankton tow samples and sediments. This will make them useful for implementation in routine monitoring programs.
Musculista senhousia (Asian date mussel) is an introduced species, which can invade benthic communities to the detriment of native species. It has been recorded in southern and western Australia. Although Musculista senhousia is the only species of this genus occurring in Australia, the mytilid family is large and diverse (21 genera and 71 species). M. senhousia has a rapid growth rate and high fecundity, reaching adult size in 9 months. It is a very adaptive species, surviving in inter-tidal to sub-tidal habitats, tolerating low salinities.
Corbula gibba (European clam) is one of 16 species of corbulids that occur in Australia, all of which belong to the Corbula genus. The latter is divided into four subgenera, of which the C. gibba group (Varicorbula) is represented by only one other species (C. rotalis from QLD). Corbula gibba is native to the eastern Atlantic but has been recorded in Victoria and Tasmania. It was first recorded in Port Phillip Bay in 1987 where it is now abundant, with densities of up to 250 clams/ m2. It is considered a pest because of its rapid growth rate and its ability to adapt to a diversity of environments, thereby competing with native species.
Sabella spallanzanii (fanworm) is the only large (> 300 mm) sabellid known to occur in Australia (Clapin and Evans 1995). The Sabella genus is itself not common in Australia, although other members of the parent family, Sabellidae, are well represented. While European populations of Sabella spallanzanii exhibit substantial genetic variability, the Australian branch of the species is relatively more stable (18 – 20% less variable). The fanworms colonise hard substrates such as pilings and rocks- they can then reach high population densities and are inedible to fish. They present a hazard because they alter turbulence and may impact severely on benthic denitrification. They were first recorded in Port Phillip Bay in 1988 and have also established in SA and WA. They appear to be transferred on the hulls of dredges and other vessels.