Within the Murray Darling Basin (MDB), experts have estimated a decline in native fish abundance of ~90% since European settlement. Things such as changes to the hydrological regime, habitat degradation, river regulation and infrastructure, over-fishing, and impacts from alien species are all contributing to the ongoing decline (Koehn and Lintermans 2012; Lintermans 2013). Ongoing monitoring
Some time ago, we published an article about the fishways at the Koondrook and Cohuna weirs that were constructed in late 2021. More recently, we pondered on the development of performance standards for fishways and what a good fishway looks like. Although still in development, the researchers at Arthur Rylah Institute (ARI) have been collecting
From the mighty Murray cod to the beloved Golden perch, some of our favourite native species have enjoyed the benefits of learnings gathered from the Flow Monitoring, Evaluation and Research program (Flow-MER). The program uses research to investigate how water for the environment can be used to enhance specific parts or processes of the fish
A long time ago in a galaxy (not so) far, far away ... aliens infiltrated the ranks of many native fish populations and risked their very survival. Fish may not be an alien concept to us, however, for Australia’s native flora and fauna, alien species pose a real threat. Native fish declines are a big
Global warming is an increasing threat for many of earth’s ecosystems. Climate change is rapidly and drastically altering the natural world, but what effect is this having on fish and is there anything we can do about it? We know that global warming is causing rapid increases in the temperature of aquatic ecosystems on a
Golden perch (Macquaria ambigua) are one of the most desirable species within the Murray-Darling Basin (MDB). They are widely distributed and are a common large native fish in the MDB. The species can grow up to 23kg — however, most are typically less than 5kg. Their potential size makes them a popular fish for many
‘Flow hydrodynamics’, ‘turbulent kinetic energy’, ‘rheotactic behaviour’ - whilst these terms might not mean much to you, they are essential parts of native fish migration in the Murray-Darling Basin. The Murray-Darling Basin is one of the most regulated river systems in the world, home to over 10,000 barriers preventing fish from migrating. These barriers
Native fish in Australia are hardy, having adapted over millennia to live in one of the driest continents on Earth. However, research shows that even the hardiest of native fish species aren’t immune to the effects of human changes to natural environments. River regulation, in particular, alters aquatic ecosystems significantly, changing the natural environment and
Fish Movement Weirs and regulators in rivers and lakes can impede or block the movement of native fish, impacting their ability to migrate and move to suitable feeding or breeding areas. While all fish need to move around to some degree, ‘flow-specialists’ like Golden perch and Silver perch need to move along rivers as part
Microplastics are a global problem, infiltrating all levels of food systems and ecosystems. Now a multi-level governance issue, reaching across international, national and local scales, microplastics are most known for their impact on oceanic ecosystems, however, freshwater ecosystems are equally significantly impacted by plastics. Microplastics have been noticeably less researched in freshwater ecosystems compared to
Like many other important native freshwater fish species within the Murray Darling Basin, Golden perch (Macquaria ambigua) were immensely impacted by the 2018-19 fish kills in the lower Darling River. A 2021 study involving 18 researchers (by Zampatti et.al) looked into the species’ historical and current population demographics in the Darling River. The study provided guidance on how best to manage our
In order to recover native fish populations, the Australian Government invests a significant number of resources, particularly regarding environmental water. In order to guide this investment, it is crucial to understand how and why fish populations vary. Although there is a considerable amount known about how different characteristics of populations impact population growth, less is