Benthic Macroinvertebrate Sampling
The term “Benthic Macroinvertebrates” means animals without a backbone (invertebrate) that are large enough to see with the naked eye (macro) and that live within the substrate of a body of water (benthic). Common macroinvertebrates found in freshwaters of New Jersey include insects, crayfish, snails, mussels/clams, and worms. Benthic macroinvertebrate monitoring consists of collecting benthic macroinvertebrates from the water using a net and identifying them to at least the order level. Benthic macroinvertebrates are fairly easy to collect and identify and they don’t move too far from where they hatch. Because each macroinvertebrate has a different level of tolerance to pollution, they are good indicators of water quality conditions over time.
Most volunteer monitoring programs in New Jersey conduct some type of benthic macroinvertebrate assessment to infer the water quality conditions based on the biological monitoring results. These assessments involve integrated measures - or indices - of the composition, diversity, and functional organization of a reference aquatic community. Benthic macroinvertebrate monitoring is inexpensive, the protocol is fairly easy to follow, and it’s fun. Once you have some hands-on experience sampling the macroinvertebrates in your streams, you will begin to find that it is relatively simple to identify them. To get started, read the Biological Assessment Manual.
The Department has also developed modified indices for streams located in New Jersey's three distinct eco-regions: High Gradient Metric Index (HGMI) for the Highlands, Ridge and Valley, Piedmont Province in Northern NJ, Coastal Plain Metric Index (CPMI), and Pinelands Metrix Index (PMI). These three eco-regions have unique environmental characteristics that support different macroinvertebrate communities. By creating a separate method of scoring for each region, we can now assess a stream's health more accurately; giving us a better advantage in assessing stream health throughout the State.
The following materials are available for use by volunteer monitoring groups to record, assess, and submit their biological data to the Department:
Macroinvertebrate Data Sheet: For counting and recording the species composition of the biological community observed/collected, along with other pertintant information and observations.
Metric Scoring Sheets: Each sheet contains the information and formulas needed to convert the Data Sheet tallies into overall scores using the regional metric:
Scoring Templates: Excel spreadsheets already formatted to apply the region-specific formula and calculate the metric from the Volunteer Scoring Sheet. Do not cut and paste cells in the Excel spreadsheet because it may affect the built-in formulas:
Additional information about the Department 's Freshwater and Biological Monitoring Program is available on the Department's Web site at http://www.state.nj.us/dep/wms/bfbm/amnet.html.