Benthic Macroinvertebrates

When looking at water quality, it is key to take a look at the organisms that call the stream their home. Benthic Macroinvertebrates (BMIs) are tiny aquatic organisms which live on the bottom of streams and rivers. They are a food source for many larger aquatic organisms.


BMIs are commonly used to assess water quality in streams as they are ubiquitous, and have known “pollution tolerances”. This means that these organisms are known to be affected differently by pollution, so the BMI community will be compromised by periodic episodes of poor water quality or continuous poor water quality.

Last Fall we completed BMI sampling on 10 of our streams within the Petitcodiac Watershed. Using Environment Canada’s CABIN (Canadian Aquatic Biomonitoring Network) protocols for wadeable streams. This involved using a “kicknet” which we caught bugs in by shuffling our feet vigorously in the substrate to stir up sediment and BMIs into the water column. We can then identify these organisms in the sample and use this data to determine the relative water quality within the stream.


BMI sieve

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