Introduced Marine Species

Divers survey for introduced species. Photo by DPI&F

Marine plants and animals can be transported across thousands of kilometres of ocean on the hulls of recreational, fishing and commercial vessels, and in the ballast water of ships. Most of these organisms will not survive the journey. But, if conditions are right, those that do survive can thrive in their new environment and become pests.

There are now over 250 exotic marine species reported from Australian waters, most of which were probably introduced unintentionally with mariculture and shipping activities. Only a few of the introduced marine species are considered pests because they can threaten native biodiversity, commercial shellfish industries or port activities.

One introduced pest that has become an enormous problem in Australia is the northern Pacific seastar. The seastar was introduced, probably in ballast water, to the Derwent estuary in Tasmania in the early 1980s and has been spread in ballast water as far as Port Phillip Bay in Victoria. The seastar produces millions of young each time it spawns, can quickly reach plague proportions in areas it invades. It eats many other marine animals, and so threatens native species, as well as commercial shellfish industries.

Recently, the black striped mussel Mytilopsis sp. was found in Darwin harbour. It is closely related to the zebra mussel which was introduced from Europe into the freshwater systems of northern America. The zebra mussel flourishes in the Great Lakes area, choking waterways. Remedial engineering and cleaning of pipes and water systems to remove the zebra mussel costs about US $1 billion annually. In Australia, because the black striped mussel was detected before it could establish large populations, it was eradicated from Darwin harbour.

To ensure that introduced marine species do not establish and become pests, we need to know their present distribution and abundance in Australian ports.

Surveys for introduced marine species

CRC Reef scientists from the Dept of Primary Industries have been conducting baseline surveys in Queensland ports. These surveys aim to describe the existing marine communities and determine whether any non-indigenous species, of pest status or otherwise, are present.

The Ports of Abbott Point, Mourilyan Harbour, Lucinda, Weipa, Karumba, Townsville and Cape Flattery have already been surveyed by the group. The Abbott Point, Mourilyan Harbour and Lucinda baseline survey projects are completed and reports of these surveys are available online from the Ports Corporation of Queensland website.

Information on the Port of Townsville survey is available through the Port of Townsville web page.

During any one port survey 15 different sampling techniques are used. The sampling program is labour intensive and based on a set of baseline sampling protocols developed by Centre for Research on Introduced Marine Pests (CRIMP) in association with the Australian Association of Port and Marine Authorities (AAPMA). The protocols ensure that different agencies and research organisations across Australia follow a similar approach during port surveys and use standardised survey methods. These protocols may be viewed at the CRIMP website.

Tropical port environments differ from those in temperate waters. Therefore, the sampling techniques used for ports in tropical Australia are slightly different from the protocols developed by CRIMP. This ensures that all aspects of the biologically diverse tropical environment are considered.

Asian green mussel

The Asian green mussel, Perna viridis, has recently been discovered in Cairns port. The Environmental Protection Agency have published a brochure with further information about the mussel. The entire brochure (The Tussle with the Asian Green Mussel) can be accessed via the EPA website.

Links

Information sheets about various marine pests may be sourced from the Centre for Research on Introduced Marine Pests (CRIMP) home page.

Information about invasive species from around the world, both terrestrial and aquatic, may be sourced from a Global Invasive Species Database.