Native fish populations in the Murray-Darling Basin (MDB) are in poor condition, with altered flow regimes being a major contributor to their decline. Implementation of the Basin Plan provides the opportunity to improve flow regimes and contribute to the restoration of native fish populations.
To effectively manage water for native fish, we need to understand the flow drivers that support healthy fish populations. NSW DPI Fisheries used the latest management and scientific information to develop an understanding of the relationships between hydrology, life history requirements and population dynamics for native fish in the MDB (the Fish and Flows project). Using these relationships five different ‘functional groups’ of fish species were identified based on shared life history characteristics and responses to flow. The flow components that support these life history characteristics were then developed. These functional groups and flow relationships are now being used to simplify water management targets for fish.
Achieving more sustainable long-term outcomes for native fish through improved flow management will be significantly enhanced by undertaking parallel complementary actions that address other threats to native fish, in addition to altered flow regimes. Complementary actions include activities such as habitat restoration and enhancement (e.g. re-snagging, instream and riparian zone management); mitigating cold water pollution or hypoxic black water impacts; improving fish passage and connectivity; screening diversions to minimise fish entrainment; pest species control, and; conservation stocking or translocations in cases where native species are unlikely to recolonise rehabilitated habitats.
The use of the Fish and Flows framework at regional scales, in combination with site specific information and complementary actions, will guide water management decisions that support the recovery of native fish in a healthy working Basin.