Degradation
As a result of poor land and water management practices over the last century, a number of the State’s waterways and river fisheries are now in a degraded state.
Examples of this degradation includes:
- habitat loss both within the waterways and along the edges (riparian zones)
- alterations in natural flow regimes
- contaminants entering waterways
- erosion of riverbanks and scouring of river beds
- in-stream barriers have been erected and
- introduction of non-native plant species.
Many fish and invertebrates are very sensitive to the degradation that has taken place around them. Examples include:
- removing riparian and in-stream habitat, which removes fish shelter, spawning material and food sources
- changing water flows which can de-water preferred habitat also making fish more susceptible to predation
- contaminants directly killing fish and invertebrates
- erosion adds sediments that can smother eggs and kill some species
- erecting in-stream barriers can reduce fish movements and eliminate migrations and introduced plants can ‘choke’ waterways.