On the banks of meandering rivers, rural homesteads were built, villages were established and then towns flourished.
Of all our ecosystems, our rivers have been vital to our country's development. Yet they have borne the brunt of that development.
Today, our continent's arteries no longer pulse with raw energy, are no longer brimful of fresh-water aquatic life. Instead, they are starved of flow, impacted by weeds, and polluted by urban and rural run-off.
We have overseen the devastating decline of native fish species. Fewer than 10 percent of pre-European populations survive in our once magnificent rivers.
But through the scientific resolve of many, researchers are lending a helping hand to our native fish species. Specialised breeding programs are yielding impressive results, including FishGen, a unique program that can trace fish and their offspring through a genetic database.
At Kambah Pool on a recent, beautiful autumn day, our ecologists caught a young golden perch, took a tiny piece from a fin and released it again. This lovely fish then swam away and disappeared into the depths of the mighty Murrumbidgee River.
But its tale actually started in 2015. Testing of the sliver of fin showed this humble golden perch started its life in a hatchery at Narrandera Fisheries Centre, the child of fish parents caught from the wild a year earlier.
Our little golden perch was released into Burrinjuck Dam by the NSW Department of Primary Industries in Summer 2016. Vulnerable to predation, at the mercy of the elements, the odds were severely stacked against our little battler. Overcoming incredible obstacles, a tale of adventure assumed epic proportions.
A large flood, once common in the river but made rare by dams upstream and climate change, brought risks of being washed downstream but also an abundance of food. Our fish matured, gaining strength for the colossal challenges ahead and headed into the unknown.
The goal was to head upstream, breed with other fish, swim against the flow. Leaving Burrinjuck Dam, our golden perch entered a vast river system, encountering rocky riffles, shallow sand slugs and deep pools. The Murrumbidgee River is dynamic and daunting, especially for a defenceless fledgling fish.
A sewage treatment plant required diligent navigation, a formidable weir required tenacity. They say that timing is everything. Golden perch are known to push upstream on high flow events. With a pulse of seasonal river current, which is all too scarce these days, the time was right. Built barriers were overcome. A journey of determination continued to Kambah Pool.
On that autumn day, a species' resilience intersected with scientific innovation. A captive-bred native fish had traversed a mighty river system, signalling that with a helping hand our rivers can flow again with native species.
If this little fish breeds in the wild, and it or its offspring cross paths with ecologists, FishGen will be able to track their continuing story.
- Brett McNamara is with ACT Parks and Conservation Service.
