Fish and other aquatic organisms respond in predictable ways to changes in land use and water flow patterns. This is why they can provide important information regarding the effects of both recent and historic changes in land use and flow regime, and associated changes to fringing zone, aquatic habitat and water quality.
Aquatic biota are assessed based on comparison of observed communities of fish and macroinvertebrates against expectations of communities that would occur in the absence of impacts caused by humans.
We measure the richness and abundance of native and exotic species, as well as their general condition.
To interpret changes in aquatic communities, we need to assess a wide range of data relating to habitat conditions and the various stressors that might be affecting them. This is assessed against our knowledge of the tolerances or needs of each species.