Macro-invertebrates are animals without a backbone that can be seen without the aid of a microscope or magnifying glass. Aquatic macro-invertebrates are those that spend all or part of their life cycles in water. They include many insects, crustaceans, mites, molluscs and worms.
The term ‘water bugs’ is often used as shorthand for aquatic macro-invertebrates. Scientists consider water bugs an excellent 'bioindicator' of water health. A bioindicator is a biological paramenter (eg fish, plants, frogs, water bugs) that can indicate your stream's health. A chemical indicator (eg pH, disolved oxygen, nitrates) can also be measured to determine waterway health and both are used in Waterwatch.
Water bugs vary in their sensitivity to changes in the environment and while some bugs can survive in poorer quality water, others will not. So by studying the number and types of water bugs in your stream, you can work out if your stream is in poor, moderate or good health. Click on the Water Bug Detective Guide below for some examples from the ACT Region.