The Wet Tropics has the most diverse fish populations in Australia, with over 80 species. This diversity means that our fish have very different habits and different requirements in terms of ecology and flow.
There are four different types of fish migration:
- Potamodromous - freshwater fish that are born in upstream freshwater habitats and then migrate downstream as juveniles to grow into adults
- Anadromous - these fish spawn in freshwater, migrate to the ocean and then return to freshwater to spawn
- Catadromous - catadromous fish spend most of their lives in freshwater and then migrate to the ocean to spawn
- Amphidromous - these fish are born in freshwater habitats and estuaries and then drift downstream to the ocean before heading back upstream as adults to spawn
In the Wet Tropics we typically have catadromous fish, which means that after spawning in estuaries they migrate upstream to freshwater wetlands areas, and because they migrate when they're small juvenile fish, they are less able to navigate potential barriers such as weirs, dams etc.
For more information about 'pushing fish uphill', watch this short video presentation: