Murray River Cod
- Commercial and recreational overfishing
- Altered water conditions
- Invasive fish species
The Murray River Cod is an apex predator fish species that exclusively inhabits the slow-flowing streams and rivers of Australia’s Murray-Darling River system.
This large, elongated freshwater cod whose other names include Mary River Cod, Murray Perch, Greenfish, and Queensland Freshwater Cod is a voracious feeder and has a very interesting diet that consists of other fish, snakes, frogs, and mice as well as ducks and turtles.
The Murray River Cod is seriously affected by unregulated fishing – both for commercial purposes and recreational activities – between the mid-1800s up to mid-1900s. What is left of the population these days has to deal with continuous loss of in-stream covers, dead trees, riverside vegetation – which means lack of suitable habitat area for this fish species as well as limited food supply.
Construction of dams and weirs also contributed to the continued decline of its population. It can cause blackwater events such as flooding which produces low oxygen levels and instantly kills adult individuals. Cold water temperatures below 13°C, on the other hand, will also ensure fatal death for fish eggs and larvae.
Higher water flow is a major challenge during the breeding season as it forces young fish to be pumped out of the river and into surrounding lands.
Introduction of wild fish species within its natural habitat also means competition for food and potential transfer of viruses and diseases.