Marine Pests

Marine pests are foreign or alien marine plants or animals that have invaded locations outside of their native geographic range. As with land-based feral animals and weeds, marine pests threaten Kangaroo Island’s unique marine environment and associated industries.

Kangaroo Island's (KI) first marine pest discovery was in 2008, when a specimen of the European fan worm (Sabella spallanzanii) was found on Kingscote Jetty during a Reef Watch dive. Natural Resources Kangaroo Island’s coast and marine program has been working on keeping KI pest-free, by undertaking regular surveys and determining risks from visiting recreational vessels. During this time we have also managed to uncover and eradicate small populations of European sea squirt (Ciona intestinalis).

There are several marine pests which have already made South Australian waters home (and many more found elsewhere in Australia), but have not yet become established on KI. Please report any sightings of these species to Natural Resources KI. Staff will then be able to positively identify and remove the offending pests if required.

How can you help?

Boats (especially those which are not used often) have the potential to spread marine pests.

The most important preventative action is one that boat owners normally do anyway, i.e. boat maintenance, such as regularly cleaning the hull and applying antifouling paint. Not only does this extend the life of your boat and gear and reduce boat running and maintenance costs, it protects the health of our marine waters.

If you have arrived in Kangaroo Island waters and suspect that you might have brought a marine pest along on your trip, report it to Natural Resources KI. Staff will assess if it is a pest or not, and remove offending individuals. This is a free service. The same goes if you think you have seen a marine pest whilst undertaking recreational activities on or around the water. It is wise to write down a good description of where you saw it (or a GPS location) if possible so the site can be easily found again.

Please don’t try to remove these species on your own, there is a chance they could spread if touched.

Priority marine pests

Aquarium Caulerpa

Common name: Aquarium Caulerpa
Scientific name: Caulerpa taxifolia
Transferred by: Regenerating from fragments left on fishing or boat gear
Impacts: Smothers native algae and seagrass. Can establish vast beds degrading fish habitat and reducing species diversity.

Asian Date Mussel, Asian Bag Mussel

Common name: Asian Date Mussel, Asian Bag Mussel
Scientific name: Musculista senhousia
Transferred by: Ballast water and biofouling
Impacts: Can outcompete filter-feeding aquaculture species for food, forms dense mats which smother seagrass and can significantly alter habitat.

European Fan Worm

Common name: European Fan Worm
Scientific name: Sabella spallanzanii
Transferred by: Biofouling and ballast water Impacts: vigorous coloniser causing nuisance fouling on aquaculture, infrastructure and vessels, competes with aquaculture species for food, forms vast, dense colonies which outcompete native species and is known to alter food webs.

European Sea Squirt

Common name: European Sea Squirt
Scientific name: Ciona intestinalis
Transferred by: Biofouling
Impacts: Nuisance fouling of aquaculture infrastructure, can out-compete native species

European Shore Crab

Common name: European Shore Crab
Scientific name: Carcinus maenas
Transferred by: Ballast water and biofouling
Impacts: Outcompetes native crabs for food and habitat. Has been implicated in the decline of native shellfish populations.

Northern Pacific Seastar

Common name: Northern Pacific Seastar
Scientific name: Asterias amurensis
Transferred by: Ballast water and biofouling
Impacts: Responsible for killing large numbers of many native species. Can have major impacts on aquaculture, particularly oyster and mussel farms.


History of marine pests on Kangaroo Island  

Since the first marine pest discovery in 2008, several more infestations of European fan worm have been discovered at Kingscote and in Bay of Shoals, as well as isolated individuals on boats at American River. These occurrences have been linked to vessel traffic from infected mainland ports. In particular, Wirrina was identified as the primary source of invasions from yachts and ferries that berthed in the marina.

In 2011, project staff analysed vessel voyages using Volunteer Marine Radio records and identified high-risk entry points. In response to these findings, the Coast and Marine Program undertakes regular surveillance activities at key ports on KI to detect incursions (early infestations). Surveys have been conducted across the island as well as at Cape Jervis where the SeaLink ferry docks. Natural Resources KI has also initiated an education program to improve community awareness. This includes:

  • installing signs at boating facilities at Kangaroo Island, and mainland ports 
  • distributing fact sheetsbrochures and stickers
  • providing training in marine pest identification to local industry and community groups such as the Coastguard and oyster growers
  • providing workshops for boat owners on vessel sanitation practices.

Kangaroo Island participated in trials in 2011 and 2012 to develop new detection methods of European fan worms on a broader scale. These trials were a collaboration with South Australian Research and Development Institute (SARDI) Aquatic Sciences which used DNA analysis to detect if pest species were present in Kangaroo Island waters.

Early results indicated European fan worms spawn earlier than expected, as larvae were detected in May but not in the subsequent winter months.

The Coast and Marine Program will continue to focus on marine biosecurity in the coming years to detect and eradicate marine pest infestations and continue to safeguard KI's rich native marine biodiversity.

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