The maintenance of genetic diversity depends on the survival of all the aquatic life within an ecosystem including fish. In a healthy environment, the surroundings interact with the freshwater ecosystem in several vital ways, including:
- bankside (riparian) vegetation acts as a filter, and provides wood and leaves for nutrients and habitat;
- insects that fall into the water from vegetation provide food;
- shade keeps the water cool and reduces the growth of algae;
- roots stabilise banks and provide shelter for fish;
- plants, rocks and wood in the water provide shelter, spawning substrate and sources of food.
Pest fish and plants can have a negative impact on biodiversity. So preventing the spread of pests (including fish species, aquatic plants, algae and fungal diseases) is important ongoing work of the Service.
Trout species, which are introduced but acclimatised, can have a negative impact on some native fish, either directly through predation or indirectly, by competing for food and habitat. Only a few waters within Tasmania remain trout free, and the Service is committed to maintaining this status for the conservation of native species. It is a serious offence, therefore, to transfer any fish from one water body to another, even to a different section of the same stream.
The Service manages the conservation of native fish species through monitoring and planning in conjunction with threatened species work, and provides advice to other government agencies and community groups on fish habitat requirements.