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Aquatic pests

What are aquatic pests?

Aquatic pests can be found in both our marine and freshwater systems including Port Phillip Bay and the Yarra River. Pests include fish and other animals or aquatic plants that have set up residence in locations they would not normally be found. Their introduction can be a result of species extending their range due to global warming, intentional releases, aquaculture escapes or unintentional actions.

For an in-depth list please visit Victoria’s aquatic pest species.


What are the impacts of aquatic pests?

  • Aquatic pests can have a negative effect on commercial and recreational activities such as fisheries, tourism, aquaculture and ports.
  • Native aquatic species and communities can be displaced through direct predation or through competition for food and habitat.
  • Parasites and diseases can be spread by pest species which can infect native species and communities.
  • Natural habitats can be altered and degraded, by stirring up sediments and decreasing light for plant growth.

Biofouling (the accumulation of microorganisms, plants, algae, or animals) can cause considerable damage to vessels, the hulls and seawater systems. For example, cooling water intakes can become clogged, resulting in overheating and damage to the boat’s motors.


Common freshwater pests


A European carp swimming in front of aquatic plants and rocks

European Carp. Image source: Gunther Schmida. Creative Commons

Common marine pests

It is estimated that a third of the non-indigenous oceanic species in Australia have arrived via ships’ ballast water. Other aquatic pests have entered Port Phillip Bay on the hulls of ships, anchor chains, fishing gear or recreational equipment.


European shore crab

European shore crab. Image source: Julian Finn. Museum Victoria

How are aquatic pests being managed?

Actions to improve our environment – stopping the spread

Prevention rather than cure is the best approach when it comes to managing pests. They are almost impossible to get rid of once they have arrived, so it is much more effective to stop them spreading in the first place.


Managing the impacts of freshwater pests

Freshwater fish pest issues are currently managed by the Department of Environment, Land, Water and Planning (DELWP) through the Vertebrate Pest Committee (VPC) which comprises state and commonwealth government agencies. They provide advice on:

  • Freshwater pests, in particular, prioritising species and assets for research and management action.
  • International best practice for freshwater pest fish management.
  • Identifying new freshwater fish with pest potential.

Alligator weed

Alligator weed. Image source:  Department of Environment, Land, Water and Planning.


Managing the impacts of marine pests

DELWP is working to develop a nationally consistent approach to managing marine pests in Victoria, which includes:

  • Continually improving understanding of the effects of marine pests.
  • Co-ordinating management and control activities.
  • Regulating commercial and recreational fishing and shipping industries to reduce the likelihood of spreading marine pests.
  • Responding to new marine pest incursions.

The Federal Department of Agriculture and Water Resources makes rules to control the exchange of ballast water of internationally arriving vessels through the Australian ballast water management requirements. Within Victoria, the Environment Protection Authority Victoria (EPA) regulates and monitors the exchange of ballast water by vessels.


Stem of Japanese kelp

Japanese kelp. Image source: Julian Finn. Museum Victoria

Environmental citizenship

Through strong environmental partnerships the Victorian government aims to encourage a new sense of environmental citizenship, where individuals, communities, businesses and other organisations take a more active and shared responsibility in efforts to support our environment.


What you can do to help protect our waterways

All boat owners and users have an important role in stopping these pests. You can protect Port Phillip Bay catchment by keeping your boat and equipment clean and following these simple steps:

  1. Dislodge all plants and animals and bin them.
  2. Drain water from your boat and gear. Try not to let it drain back into the water.
  3. Dispose of unwanted live bait in a bin.
  4. Douse your boat and gear with freshwater. Try not to let it drain back into the water.
  5. Dry your boat and equipment.
  6. Don't forget to apply an authorised antifoulant as appropriate.

Aquatic pet owners need to be aware of the consequences to native habitats and species when releasing pet fish, snails, turtles, plants etc. into waterways.

There are also many organisations and groups involved in maintaining the water quality of the Yarra River and the bay. For more information on community groups go to the How you can help page on this website.


Reporting unusual behaviour

  • If you suspect you have seen a pest, please contact DELWP Customer Service Centre (136 186) or visit report a pest.
  • If you suspect someone of keeping or selling noxious species, contact the fisheries offence reporting line on 13FISH (13 3474).

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