Marine pests

What is a marine pest?

Marine pests are plants or animals, usually introduced from overseas, that have a significant impact on our marine industries and environment. They can include mussels, crabs, seaweeds, sea stars and other marine species. However, not all marine pests are from outside Australia. Some are native to other regions of our country and have been transported into NSW, for example, through domestic shipping or the aquarium trade.

How are marine pests introduced?

Marine pests have been introduced into Australian waters in various ways, including in ballast waters, attached to the hulls of international ships, or imported deliberately as aquarium or aquaculture species. An estimated 250 introduced marine species have been introduced into Australian waters in these ways.

Which species are marine pests?

What impacts do they have?

Marine pests can have severe ecological and economic impacts. For example, they can take over large areas of habitat to the detriment of native species. Some prey directly on native species or compete with them for food.

Pest species can also cause considerable economic damage. Infestations of marine pests can impact on marine industries, such as aquaculture, commercial and recreational fishing and boating, tourism and even international and domestic shipping. Some marine pests, such as toxic dinoflagellates, can threaten public health.

What is NSW DPI doing about marine pests?

NSW Department of Primary Industries (NSW DPI) has developed a Caulerpa Control Plan for the noxious seaweed Caulerpa taxifolia.

NSW DPI undertakes research and monitoring on a number of introduced marine species, including Caulerpa taxifolia but also the European fanworm Sabella spallanzanii and the European green crab Carcinus maenus. Other research NSW DPI is involved in is looking at the role of artificial surfaces in facilitating invasion by introduced marine invertebrates.

NSW DPI is involved in the development of the National System for the Prevention and Management of Marine Pest Incursions ( which aims to prevent the introduction and translocation of introduced marine species (by managing ballast water, biofouling and other vectors), provide a national emergency preparedness and response capacity for outbreaks, and to manage and control introduced marine species that cannot be eradicated.

NSW DPI also has an extensive advisory program to raise awareness of marine pests including how to identify marine pests and how to help prevent their spread. For more information see links below to marine pest publications:

What can you do to help?

Members of the public, including fishers, divers and members of local environmental groups, are sometimes the first to notice a new introduced marine species or the fact that an existing pest has spread into a new area. This information can be very valuable in helping to manage pest problems.

What fishing closures relate to marine pests?

For Caulerpa closures, look under 'Recreational saltwater - General closures' on the Fishing closures page.

For Pacific Oyster Control closure, look on the fishing closures page

Related links