2019
Download
About the document
In spring and summer 2018-19, the Commonwealth Environmental Water Office, Murray-Darling Basin Authority and South Australian Department for Environment and Water jointly commissioned the University of Adelaide and the South Australian Research and Development Institute (SARDI) to undertake monitoring to characterise the zooplankton community structure in relation to changes in freshwater discharge (supported by Commonwealth environmental water), salinity and temperature and to evaluate changes in zooplankton community structure and profile in relation to salt-wedge conditions.
The monitoring showed that the prolonged low/no flow conditions leading up to and during the sampling period resulted in salinities similar to that of seawater (~35 PSU) throughout the majority of the study area and resulted in the zooplankton community being dominated by marine/estuarine species. Typical of marine zooplankton communities, abundance and diversity was generally low.
This study demonstrated that the low barrage releases in the spring and summer (November to February) of 2018-19 (ranging from 0 to 1,487 ML/day), are likely to have delivered limited productivity, despite the presence of salt-wedge conditions along the Goolwa Barrage transect. This was reflected in low abundances and diversity in the pelagic zooplankton community throughout the Murray Estuary. A better understanding of how the nuances of freshwater discharge drive food-web responses in the Murray Estuary will inform managers to improve water management to effectively increase the productivity benefits for the ecosystem and achieve specific ecological targets/outcomes.