Introduced pests and diseases pose environmental, social and economic threats through damaging the natural balance of aquatic flora and fauna.

The Aquatic Biosecurity unit deals with issues of disease in both wild and aquacultured populations, fish kills, and other factors which may impact on fish health, such as toxic algae outbreaks. Threats are managed by implementing strategies and operational policies based on assessment of risk.

Fish health management is a critical issue in the aquaculture industry, as a disease outbreak can devastate farmed populations and severely impact the short-term profitability or even long term viability of aquaculture businesses. Those who keep ornamental fish for a hobby also frequently confront disease issues, and need to be scrupulous in managing the health of their fish and preventing any diseases that do occur from spreading to other aquaria or even the wild through transfer of sick fish or contaminated materials. Outbreaks of disease also occur in the wild, where they can cause unsightly and unhealthy fish kills or even endanger populations of certain native species.

Introduced species can compete with natives for food, habitat and spawning sites, may prey on native species, and spread disease.

Translocation vectors to be managed include shipping, aquarium releases, aquaculture shipments, and deliberate stockings.

Data on distribution and population dynamics is collected to help manage pests.

Exotic weeds are also detrimental. Caulerpa taxifolia occurs in estuaries between Lake Macquarie and Wallagoot (as at November 2007). NSW DPI is using salt to control the weed, regularly mapping its distribution, and researching its impacts on biodiversity.

Some surveys, monitoring and research projects are also underway for other introduced marine pests along our coast.