The influence of changes to river hydrology on freshwater fish in regulated rivers of the Murray–Darling basin
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- Growns, I. Hydrobiologia (2008) 596: 203. doi:10.1007/s10750-007-9097-y
Freshwater fish are often used as an indicator of the response of the ecosystem to the restoration of river flows or the provision of environmental flows. The ability to model the biological response of fish depends on the capacity to establish clear relationships between changes in river hydrology and the fish assemblages in a river. The fish assemblage structure and the abundances of individual fish species were examined in relation to a hydrological index that described hydrological change in six regulated rivers in the Murray–Darling Basin. The hydrological index explained only a small amount of variation in fish assemblage structure. In addition, the abundances of individual fish species were only weakly correlated with the index of flow deviation. It is suggested that these results make the modelling of responses of fish assemblages to environmental water allocations unfeasible at a large scale and that future studies should concentrate on potentially more simple responses, such as the relationships of fish spawning and recruitment to specific aspects of river hydrology.