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Biomonitoring

What is Biomonitoring?

Stonefly being held by DEC personnel.

Biological monitoring provides information on the health of an ecosystem based on which organisms live in a waterbody. The types and numbers of organisms collected from polluted water differ from those collected in clean water, helping us determine "how clean" (level of water quality) the water is and to detect water quality changes over time.

Macroinvertebrates, fish, and algae are all widely used in biomonitoring. Although DEC collects information on all of these aquatic organisms, macroinvertebrates are collected and analyzed the most.

When and where are biomonitoring data collected?

Each major watershed in the state is monitored on a five year schedule as a part of our Rotating Integrated Basin Studies (RIBS) program. Each sampling season (June-September), three or more basins are sampled following this schedule.

2019 Sampling


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In 2019, DEC's Stream Biomonitoring Unit is collecting macroinvertebrates from approximately 75 streams and rivers in each of three watersheds: St. Lawrence, Genesee, and Delaware, as part of the RIBS Screening Network.

How are biomonitoring data collected?

DEC adheres to the procedures outlined in the Standard Operating Procedure: Biological Monitoring of Surface Waters in New York State, 2018 (PDF) to collect, process, and analyze biomonitoring data. This ensures uniformity of methods and accuracy of data when performing biological monitoring of surface waters in New York State. View the Biological Assessment Profile (BAP) Fact Sheet (PDF) for more information on water quality assessment using biological data.

How does DEC use biomonitoring data?


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  • NYSDEC
    Stream Biomonitoring Unit
    Division of Water
    425 Jordan Road
    Troy, NY 12180
    518-285-5627
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