Pest Fish

A 'pest fish' is either a native or exotic fish that has a negative impact on species living in the region. Impacts include disease, predation, competition for food and habitat, and degradation of habitat and water quality.
Pest fish management in Tasmania covers the management, monitoring and control of identified pest fish species, particularly those species listed as ‘Controlled Fish’ under the Inland Fisheries Act 1995.  These include European carp (Cyprinus carpio), all species of mainland yabbies (Cherax spp.) and Eastern gambusia (Gambusia holbrooki). This means they have the potential to cause significant environmental harm. A person cannot possess these fish or release them into any inland water in Tasmania, including an aquarium.

Since the discovery of carp in Tasmania in 1995, the Service has invested significant resources in a Carp Management Program, specifically funded by the State Government to deal with the problem of carp. This has resulted in the sucessful 'fishing down' of carp populations in Lakes Sorell and Crescent and the containment of the spread of carp to these waters.

Three species of introduced fish, goldfish (Carassius auratus), redfin perch (Perca fluviatilis) and tench (Tinca tinca) are regarded as undesirable introduced pests. Controlling the spread of these species outside of their present distribution is a priority for the Service.
Effective fishery management requires anglers to comply with rules and regulations, and be willing to help reduce the spread of pests in Tasmanian waterways. Anglers must not move fish from one water body to another, and may not bring live fish into Tasmania, as both the fish and the water in which they are transported can harbour diseases, parasites, exotic aquatic plants and animals (eg. water snails may harbour parasites of livestock). The Service has extensive powers to deal with pest fish offences with penalties up to $10 000.
The Inland Fisheries Act 1995 covers the entry into Tasmania, of any fish species capable of living or breeding in the State's waters. This includes imports made for fish bait, aquarium pets and aquaculture.

Negative Impacts of Introduced Fish

Exotic fish, or the water in which they are kept, if released into the environment, may harm native and recreational fisheries, the aquaculture industry and the ecological integrity of the aquatic systems. They can:

• Destroy native or recreational fisheries by establishing breeding populations which compete for food and habitat;
• Spread diseases which may infect native fish or other aquatic animals;
• Spread parasites either directly with imported fish, or indirectly with the holding water or with exotic aquatic plants which may carry animals (eg. Water snails which harbour parasites of livestock);
• Alter habitat which may displace and reduce populations of native fish and trout (eg. European carp destabilises bank vegetation and cause water quality deterioration – muddied streams and lakes);
• Cause other problems such as introduction of noxious weeds which may thrive in rivers, creeks, lakes and irrigation channels, choking waterways, blocking drains and impeding navigation.

There are a number of ways in which users of inland waters, particularly anglers, can Help Prevent Pest Fish including their introduction to Tasmania and spread within the State.

Prohibited Imports and Activities

Throughout Australia, millions of dollars are spent annually in attempts to control or eradicate invasive pests.  Tasmania has strict legislative and quarantine procedures designed to minimise accidental introductions of exotic plants and animals in order to protect native fisheries and the integrity of Tasmania's aquatic ecosystems. A number of Prohibited Activities attract large fines of up to $25,000.