The Wet Season is over in the Northern Territory, and Hydrobiology is preparing to head to the waterways surrounding the former Rum Jungle uranium-copper mine as part of a major rehabilitation project. But this isn’t the first time Hydrobiology has visited Rum Jungle. In 2014 and 2015, Hydrobiology conducted detailed surveys of the aquatic ecosystems in the area, particularly in the East Branch of the Finniss River.
Due to metal-contaminated leachate from the Rum Jungle uranium-copper mine, the East Branch of the Finniss River has been exposed to elevated copper concentrations for over 40 years. The Hydrobiology team recorded that the population of black-banded rainbowfish (Melanotaenia nigrans) were abundant in this aquatic system, even at very high metal concentrations. This particular rainbowfish population is actually the second recorded case in the world of freshwater fish adapting to heavy metal pollution, as they have developed specially-adapted gills that enable them to survive heavy metal pollution levels deadly to other species. Furthermore, these rainbowfish are responsible for reducing the likelihood of species at higher levels of the food chain suffering from the toxic effects of copper, because their specially-adapted gills work by reducing or all-together blocking the amount of copper absorbed, enabling them to halve the amount of copper “bio-concentrated” in their bodies.