MDFRC - Projects - Habitat - Darling River fish

Darling River fish - Habitat investigation

January to June 2009

Report to LMDCMA

The overall aim of this project is to quantify the physical character of

habitats and the associated structure of fish assemblages at sites previously studied as part of the

recently completed MDFRC project 'The impact of drought on water quality and fish communities

within refuge pools of the Lower Darling River' (Wallace et al. 2008).

The project objectives are to:

(a) characterise the available structural habitat of refuge pools and adjacent runs at those sites

investigated by Wallace et al. (2008)

(b) enable examination of which, if any, habitat characteristics define the species, size and number

of fish associated with snags of particular character at those sites investigated by Wallace et al.

(2008)

The project objectives will be addressed by:

1) Quantifying the density, plan-form area, complexity, orientation and aspect of large-woody

debris (snags), and determining the distance between snag complexes, by employing

contemporary visual (surface) and acoustic (underwater sonar) mapping techniques

2) Quantifying the species composition and distribution of emergent aquatic macrophytes

3) Examining instantaneous water quality (pH, EC, NTU, DO, Temp) along 3X vertical and 3X

longitudinal transects in run and pool habitats

4) Examining the assemblage and population structure of fish in relation to individual habitat(s),

(i.e. at the micro-habitat scale; individual snag / vegetation unit)

This information will be useful for the management of refugia for native fish in the lower Darling

River, as well as for future habitat rehabilitation works undertaken by the LMDCMA and other

agencies in the Murray-Darling Basin. The knowledge gained here may inform the appropriate

structure, number and spatial location of snags best suited to achieve a host of fish

population/community maintenance or rehabilitation goals.

Darling River fish - Habitat investigation