In Magela Creek, downstream of the Ranger Mine, sudden fish-kill events are known to occur occasionally. Are these events in any way related to impacts of mining activity?
‘Fish-kills’ are a relatively common natural phenomenon that occurs in tropical wetlands across the Top End over the Dry Season. As water levels in billabongs decrease over this time fish become more crowded, which can cause behavioural stress and makes the fish more susceptible to disease. Oxygen depletion also tends to occur late in the Dry season. This can happen quickly and the sudden death of almost all the fish in the billabong can occur. Such events have been well documented in billabongs of the Magela Floodplain, and in billabongs of the Mary River, Adelaide River, and South Alligator River catchments, and can occur after the first rain storms which wash large amounts of organic matter into billabongs. This material decomposes and uses up the oxygen, sometimes all of it. Sometimes strong winds can mix deeper water with no oxygen with a shallow layer of oxygenated surface water, so that there is not enough oxygen for the fish. For further information regarding fish kills please
