Battered Barwon raises eel fears

August 23, 2021

A recent overflow of the West Barwon Reservoir has laid bare environmental concerns for the Barwon River following years of deterioration, which has raised fears for culturally significant species.

Poor waterflows, weed infestations and impacts from human interference such as the dam and introduction of angling species have taken their toll on the local waterway, with locals calling for urgent action to fix long-running issues.

But advocates hope the tide could soon turn, as the State Government reviews its water resource strategy and community groups gain extra support and momentum as the issue gains attention.

The West Barwon Reservoir reached capacity for the first time in seven years last month, thrilling river watchers with strong flows rarely seen following years of decline.

While the overflow attracted hosts of visitors to witness waters cascading down the dam wall, locals had a different goal further downstream — an eel hunt.

Native eels have used previous overflows as an opportunity to escape up the man-made dam wall and continue their natural migration along the river, which became “teeming” with the animals during past events.

Short-finned eels are born in salt water but spend most of their lives living in fresh water such as rivers, before returning to the ocean to breed then die.

Forrest mum Catherine Roberts was among the locals who took their torches to the river with family during evenings when the river was at full flow in the hope of catching a glimpse of the migration event.

The activity was supposed to lift spirits amid lockdown restrictions at the time and provide an uplift and variety to the day’s hour of permitted exercise.

But this spill was different. Locals haven’t witnessed any eel migration, and Ms Roberts said their absence had heightened fears of the species’ future in the habitat.

“Studies tell us these are the things that impact native species, and we’ve got all of them; poor river condition, introduced species, a huge, giant concrete weir – and it’s about time something was done about it,” she said.

“Downstream has largely been remediated, it’s time we had a strategy to fix what’s happening here at the Upper Barwon and at the dam wall.”

The Corangamite Catchment Management Authority said it hadn’t specifically monitored eel migration during the spill, but acknowledged the species’ population was on a downward trend in the Barwon River and elsewhere.

The authority also said seasonal factors likely contributed to the lack of migration, because eels preferred warm waters to return to the sea.

“Downstream migrations tend to occur in late summer and autumn, so the spill may have been a bit late to trigger that migration,” a CCMA spokesperson said.

Impacts to the river’s eel population would be a substantial blow to the region’s history.

First Nations peoples who lived in the area relied heavily on the eel as a food source, and the river and its estuaries were central to pre-settlement tribes’ way of life.

But stakeholders and advocates say the eel fears are endemic of deep-rooted problems with the river.

Today, the river is vital for agriculture and nearby landholders have had input in remediation methods for issues like willow and glyceria infestations and to reintroduce native vegetation to improve water quality, reduce erosion and reintroduce habitat.

Victorian Fisheries Authority have also released about 6400 brown trout into the Forrest dam in the past year, introducing a potential eel predator to the ecosystem.

A 2019 report into the river’s health found the Barwon needs 29 gigalitres above Winchelsea to return the river to 70 per cent of natural flow and help reverse the worrying trends.

It currently has 1GL available for environmental use, which CCMA said “is deployed in a very targeted way”.

But exactly how to return the river to full flow and protect the native species remains a challenge for authorities.

CCMA installed elver ramps last year specifically aimed at helping eels move past dam walls, following a 2016 study into the impacts of man-made barriers on fish migration.

The State Government’s environment department DELWP is currently forming its Sustainable Water Strategy for the region, which aims to safeguard the sustainability of water resources.

A draft plan is due out next month, which will then open for public consultation.

CCMA said it had input into the early drafts of the strategy and hopes it helps secure the long-term health of the Barwon, and Ms Roberts said the process was also a chance for the community to raise the issues important to them.

“Unless there’s public spotlight on it, nothing will happen,” she said.

“This is the perfect time to get the public talking about water regulations.”