Natural causes of fish kills in Top End waterways

2001

eriss note
Bob Pidgeon,
Environmental Research Institute of the Supervising Scientist, December 2001

About the note

Fish kills are the sudden death of large numbers of fish. These events are very common in inland waters of the Top End. It is a rare year when at least one kill is not reported and in some years there are many reports. Most of these fish kills are the result of natural causes. However, it is well known that such kills can also result from pollution of water by urban, agricultural and industrial effluent.

This eriss note discusses the causes of fish kills, where and when they happen, the natural processes that cause them such as lack of oxygen, naturally toxic water and disease, diagnosis procedures for fish kills, and what signs to look out for.