Macroinvertebrates are aquatic bugs large enough to be seen without a microscope and are sensitive to organic pollution. Our water monitoring programme includes the traditional stream quality assessment based on analysing water quality and chemical data. However this technique often misses “pulses” of stress like pollution events because the change in water chemistry is short lived. The composition of the macroinvertebrates community can “record” a pulse of stress because the diversity and abundance of the biotic community will take longer to recover. Hence the macroinvertebrates community are more integrated and can be a better measure of overall stream health.
MCI>120 : Excellent
100<MCI <120 : Good
80<MCI<100 : Moderate
MCI<80 : Poor
HBRC and the Whangawehi Catchment Management Group have been carrying out the MCI indexing for several years. Follow the link for more information :