Bioassessments measure both the physical condition of a water body, and the integrity of the associated biological communities. Adding physical and biological metrics to chemical and toxicological assessments provides a more comprehensive evaluation of the condition of a given body of water, and provides a means with which to quantitatively separate impacts of non-chemical substances, such as sedimentation and habitat degradation, from the effects of chemical contaminants and changes in the hydrological regime. While benthic macroinvertebrate sampling results integrate the effects of changes in habitat and water quality over time, and exhibit sensitivity to these parameters, program study design is key to being able to separate these potential causes of observed impacts on the biological community.
Dr. Bailey of Nautilus has considerable experience in effective program study design, annd the use of bioassessment data to determine the presence of adverse effects. Nautilus staff are familiar with California Stream Bioassessment Procedures (CBSP) and have completed California Fish and Game's program in this specialty.