Fish life
KEY FINDINGS FROM OUR 2024 REPORT CARD
The 2024 Townsville Waterways Report Card includes updated freshwater fish data for the second time since 2021.
61 species of fish were caught during sampling to inform the Report.
Fish grades reflect two factors: the proportion of indigenous fish species present against expected numbers, and the proportion of non-indigenous (alien or translocated) fish species present against total numbers.​​​
In both Ross and Black Basins, fish grades have declined against the previous monitoring period.
In 2024 the Ross Basin retains a ‘moderate’ grade for fish, but scores lower against the last monitoring period due to an increased proportion of non-indigenous fish found in the basin.
The Black Basin receives a ‘good’ grade, but monitoring does show a reduction in indigenous fish numbers.
Why fish indigeneity matters
The balance of indigenous and non-indigenous (invasive) fish in a waterway can be a strong indicator of water health.
Indigenous fish species are typically adapted to the local environment and have evolved within the natural ecological framework of the waterway. Their presence in healthy numbers indicates a stable and functioning ecosystem.
Conversely, a proliferation of invasive fish species, which are often introduced from other regions or through improper aquarium disposal, lack natural predators or controls. They can disrupt native ecosystems by outcompeting indigenous fish for resources. Invasive fish can also have a negative impact on water quality and biodiversity, compromising the overall health of the waterway.
