Science

Aquatic Biological Monitoring

Aquatic biomonitoring measures changes in biological communities (for example, fish, benthic invertebrates, and algae) in order to assess the health of aquatic ecosystems. Biomonitoring is complementary to traditional physical and chemical monitoring. Biological monitoring can measure impacts of cumulative stressors including impacts from chemical interactions, contaminant pulses, or unknown contaminants that are difficult to capture with routine chemical sampling.  Other stressors that may be captured by biological monitoring include the presence of exotic species, habitat degradation in the water body or surrounding land, climate change, and fluctuations in water quantity.

Reference Condition Approach

CABIN employs the Reference Condition Approach as the principal method for site assessments. RCA study design begins with the identification of a priority area or region of concern, based on hydrological (basin, sub-basin) or biogeographic (ecozone, ecoregion) boundaries. Reference sites are then selected where anthropogenic effects are minimal. A bioassessment model is developed from the reference site data. This model defines the range of biological communities that should be found at a site if the site is not affected by human activities.

Potentially impaired (or test) sites are assessed against reference sites using the bioassessment model. The divergence between the benthic invertebrate communities at reference sites and a test site indicate the extent of impairment. The assessment of a test site is presented in an ordination plot. CABIN defines four assessment categories based on confidence ellipses around a group of reference communities: similar to reference, mildly divergent from reference, divergent from reference, and highly divergent from reference.