Recent highlights from the Flow-MER Program

Science improves our understanding of how plants and animals respond to water for the environment and informs how environmental flows can best support them in the future.

As part of the CEWO’s Monitoring, Evaluation and Research (Flow-MER) Program, quarterly newsletters provide an update of recent monitoring, evaluation and research activities and preliminary observations and findings in the following Selected Areas:

The information is used by water managers to facilitate real-time adaptive management of Commonwealth environmental water. For more information about the Flow-MER Program, please visit the Flow-MER website.

Map of river system in Eastern Australia, highlighting the selected areas

Selected Area Highlights from Issue 12 Outcomes Newsletters (April-June 2022)

Junction of Warrego and Darling rivers

Good numbers of juvenile spangled perch and golden perch were caught during March surveys between Bourke and Louth, suggesting recent recruitment.

Dissolved oxygen levels in the Barwon Darling River has consistently improved since the large flood event at the end of 2021. Levels have remained above 5 mg/L at most sites, which is considered within the normal range for the river.

More detailed information is available in the Warrego-Darling Issue 12 newsletter.

Gwydir River System

Vegetation continues to be in good condition. Evidence of a third coolibah recruitment event in the Gwydir wetlands since Autumn 2021 was also observed.

Breeding surveys for colonial nesting waterbirds observed 9 main colonies, with 8 located in the Gingham. This included 14 species and a total of 25,000 – 30,000 nests.

More detailed information is available in the Gwydir Issue 12 newsletter.

Lachlan River System

Early observations from research projects focusing on river flow impacts on aquatic food webs suggest an abundance of glass shrimp during recent high flows, and the importance of slow-flowing water areas such as billabongs as critical habitat for zooplankton.

Two watering actions occurred to maintain water levels for pelican breeding in Lake Brewster and to maintain off-channel hydraulic and longitudinal connectivity along Merrowie-Box Creek from Cuba Dam to Chillichil Swamp.

More detailed information is available in the Lachlan Issue 12 newsletter.

Murrumbidgee River System

April monitoring in Yanco Creek using fyke nets caught a juvenile freshwater catfish, once a common fish in the area, but now considered an endangered population. In June 12 adult golden perch were caught through fyke nets and electrofishing at Tala Creek and Lake.

14 colonial waterbird breeding species were confirmed across 29 active colony sites, including large pelican and ibis colonies active in the Gayini Wetlands. 8 rakali were captured and released along Yanko Creek.

More detailed information is available in the Murrumbidgee Issue 12 newsletter.

Edward/Kolety−Wakool river systems

Larval sampling has confirmed that river blackfish are expanding their range in the system. River blackfish are a little understood species of freshwater fish that occurs in the Murray-Darling Basin, a positive sign for the future of the population.

The extent of eelgrass in the Wakool River has increased at several sites, providing an important source of food and habitat for fish and other aquatic animals.

More than 75 people attended the Community Field Day at the Four Posts Camp in May. The day began with a Welcome to Country and Smoking Ceremony, followed by knowledge sharing about monitoring and research.

More detailed information is available in the Edward/Kolety-Wakool Issue 12 newsletter.

Goulburn River

Monitoring has highlighted how environmental water delivery before summer can assist in priming river banks for recovery during the growing season.

An abundance of native fish (trout cod, unspeckled hardyhead and obscure galaxias) were recorded – the highest number since monitoring started.

Shrimp abundance increased at upstream sites in Jan/Feb, with Kirwans Bridge supporting the largest number, suggesting the importance of vegetation.

More detailed information is available in the Goulburn Issue 12 newsletter.

Lower Murray River

Golden perch eggs and larvae have been found in most larval fish samples, and have been the most abundant native large-bodied fish identified so far.

The Indigenous Ecology in Action workshop was held on 21-22 June, where Indigenous students and teachers from Renmark high school spent time on country learning about cultural values, western science and traditional knowledge.

More detailed information is available in the Lower Murray Issue 12 newsletter.