You are here:
Fisheries / Aquatic Biosecurity / Aquatic pests

Aquatic Pests

Aquatic pests are non-indigenous plants or animals, whose introduction, does or is likely, to have a significant detrimental impact on the aquatic environment. They may threaten the biodiversity and abundance of native species, or they may adversely impact on commercial and recreational industries such as fisheries, tourism, aquaculture and port industries. Aquatic pests are invasive species and may come from numerous taxonomic groups including molluscs, fish, crustaceans, echinoderms, sponges, algae and ascidians, amongst others.

Aquatic pests are managed under the Fisheries Act 1998.

Click here to view the complete list of aquatic pests listed under Schedule 1 of Fisheries Regulations.

In accordance with Fisheries Regulations (17) a person shall not move diseased or contaminated fish or aquatic life or an aquatic pest from one place, water catchment or storage unit to another place, catchment or storage unit.

For further information on Fisheries Legislation and Regulations, please visit the Legislation page.

Noxious fish

Noxious fish are species that are considered to pose significant environmental and economic risks by threatening native species, ecosystems, human health, or industries that rely on our aquatic environment.

Noxious fish cannot be imported into the NT, and fines of up to $20,000 apply for the importation or possession of species on the noxious fish list.

A person who sees a fish or aquatic life that the person knows or suspects to be a noxious fish or aquatic pest must, as soon as practicable:

• Report the sighting to Fisheries; and
• Provide any information about the sighting that may be required.

Marine Pests

What impacts do Marine Pests have?

Once established, marine pests can wreak havoc with natural aquatic ecosystems, competing with, preying upon, and displacing native species and modifying their habitats.

Marine pests can also cause considerable damage to structures and vessels. Marine pests foul the hulls and seawater systems of boats which can reduce speed and increase fuel use. Marine pests can also clog cooling water intakes resulting in overheating and damage to boat motors.

In March 1999 the black striped mussel was detected in plague proportions in Darwin marinas. The threat to commercial and recreational fishing, aquaculture, tourism and port industries of northern Australia resulted in $2.2 million being spent to eradicate the pest species.

How do marine pests get here?

Marine pests are great hitchhikers. They can be spread via internal seawater systems on boats, such as inside pipes, or in ballast and bilge water. They may be introduced by attaching to boat hulls, or on anchor chains, fishing gear, and other recreational equipment. They may also be introduced as aquaculture species or via the aquarium trade.

What are we doing to stop them?

International boats intending to enter Darwin marinas must pass a hull inspection and undergo treatment of their seawater systems. Aquatic Biosecurity incorporates a monitoring component which documents water quality, and records the presence or absence of aquatic pests in Darwin Harbour and it's marinas, as well as in Gove Harbour, Melville Island and Groote Eylandt. The Aquatic Biosecurity unit also works closely with Indigenous Sea Ranger Groups around the Northern Territory so as to enhance community awareness of marine pests, and also to expand the monitoring to remote areas that may be susceptible to pest incursions.

What you can do to help?

• Regularly clean and check seawater systems on your boat.
• Keep clean and antifoul the hull of your boat every year.
• When cleaning your vessel or any gear, make sure that NO debris (including any organisms) is allowed to return to the water, so as to reduce the risk of introducing non-indigenous species.
• When out fishing, diving or boating, report any unusual aquatic growth or aquatic life in unnaturally high numbers.

Related Information

• Marine pest information (PDF 1.28MB)
• Black striped mussel (PDF 1.03MB)
• Asian green mussel (PDF 1.64MB)
• Asian bag mussel (PDF 1.16MB)
• Keeping Aquatic Pests out of the NT (PDF 4.3MB)

Freshwater Pests

What impacts do freshwater pests have?

Exotic fish and plants, or the water in which they are housed, when released into the environment threaten Northern Territory’s freshwater ecosystems by:

• Displacing our native fish – by competing with native fish for food and habitat, and by preying on native fish and their eggs.
• Spreading parasites and diseases - which may severely affect native fish and other aquatic life.
• Altering and degrading natural habitat - by stirring up sediments, decreasing light attenuation, increasing nutrient loads, smothering other plants, or adding to bank destabilisation and erosion.

Don't release aquarium fish and aquatic plants into our waterways

The dumping of aquarium plants into waterways can cause extremely serious problems, with the potential for many exotic plants such as water hyacinth and salvinia to choke waterways, block drainage systems and impede navigation.

Give unwanted aquarium plants and animals to a pet shop, or dispose of them in a humane manner, such as by freezing. DO NOT release them (native or exotic) into local waterways or drains.

What you can do to help

• Make sure backyard ponds are secure from overflowing in the Wet Season. Screen all outlets to prevent accidental escapes.
• Consider stocking ponds with native fish. Many native species such as gudgeons, rainbow fish, and spotted and delicate blue-eyes, offer better mosquito larvae control than exotics and are also frog-friendly (they don’t feed on native frog eggs and tadpoles).
• If you see any unusual fish or aquatic plants in waterways of the Northern Territory, please contact the Aquatic Biosecurity unit immediately with details and if possible collect a sample of the plant or fish.

Related information

• Non Native Aquarium Fish (PDF 6.8MB)
• Keeping Aquatic Pest out of the NT (PDF 4.3MB)
• Exotic Aquatic Snails in the Northern Territory
• American Ribbed Fluke Snail [ Pseudosuccinea columella]
• Tilapia - A Rising Threat (PDF 268kB)
• Have you seen these exotic Fish?