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Introduced Marine Pests in Southern Australia

 Disruptive hitch-hikers have altered Australia's cool water ecology.

Although the temperate marine environments of the northern and southern hemispheres are separated by warm tropical waters, the enormous growth in shipping traffic plying the world's oceans has enabled many marine organisms to travel to places they would otherwise never reach. Unfortunately, these organisms can quickly become established in their new homes, particularly when there are no natural predators to keep them in check.

For southern Australia, the result is that its waters are now teeming with introduced marine pests - the feral animals and plants of the sea. In 1998, the variety of introduced marine pests in southern Australian waters was estimated to be over 2,000 - and these are the ones that are documented.

You can view a long list of the known ferals (state by state, scientific names only) at the CSIRO Centre for Research into Introduced Marine Pests (CRIMP). Further information about marine pests can be found in CSIRO's Helix magazine (see our links page for these sites).

The Northern Pacific seastar (Asteria amurensis) has become well established in Tasmania's Derwent Estuary and has recently been found in Port Phillip Bay, Victoria.

This seastar occurs naturally in the waters of Korea, Japan and other temperate Pacific seas, where it feeds on many bottom-dwelling marine animals and plants and is an important part of marine and coastal communities. In its adopted Australian habitats, where it has no natural predators, its numbers can reach plague proportions.

In Tasmania, the Northern Pacific seastar has accelerated the extinction of the Derwent Spotted Handfish, the world's first marine fish to be proclaimed as an endangered species by the IUCN.


A Korean scientist checks out Northern Pacific Seastars in Tasmania's
Derwent River Estuary.

Photo by Patrick O'Callaghan.

Pests are not always mobile, with some spending their adult lives in the one place. The European fan worm, which has become established in Victoria, Tasmania, South Australia and Western Australia is a good example.

The European fan worm out-competes native worms for settlement habitat and in Victoria has the potential to disrupt the delicate cycle of de-nitrification which takes place in Port Phillip's soft sediments. The preference of the worm for silty shell beds has caused many problems for commercial fishing operations which relied on the shell beds for their harvest.

The Derwent Spotted Handfish - under threat from the Northern Pacific Seastar.
Photo by CSIRO.

In the northern hemisphere, the seasonal kelp Undaria pinnifolia forms an important part of the diet of many people. However, ships which unknowingly transported this seaweed from Japan to Australia have caused irreversible and continuing damage to the kelp forests of Tasmania and the shallow reefs of Port Phillip Bay. Visit CSIRO via our links page for more information about this introduced marine pest and others.

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