Macroinvertebrates
Aquatic Macroinvertebrates
Access key to aquatic macroinvertebrates
Since 1972, the Stream Biomonitoring Unit of the New York State Department of Environmental Conservation has used aquatic macroinvertebrates to monitor the water quality of the State's rivers and streams. Macroinvertebrates are larger-than-microscopic invertebrate animals. Freshwater macroinvertebrates include aquatic insects, worms, clams, snails, and crustaceans. Because of their abundance and their sensitivity to environmental impacts, they are widely used in biomonitoring programs for assessing water quality.
This key is a pictorial method of identifying aquatic macroinvertebrates. It is structured so the major groups of aquatic macroinvertebrates can be accurately identified primarily on the basis of photographs instead of traditional written keys that often require the knowledge of unfamiliar terminology. In the future, photographs of selected families, genera and species of macroinvertebrates will be added to the site. It is the result of the combined efforts of NYS DEC Stream Biomonitoring Unit and the Hudson Basin River Watch.
The photographs in this key were made using a stereo microscope with an attached digital camera specifically designed for photo microscopy. A magnification of between 7x to 100x was used to take the photographs. Without magnification this key may be used to identify organisms to one of the major groups of macroinvertebrates such as mayflies, stoneflies, caddisflies, beetles, fly larvae, etc. With a stereo microscope having a magnification range between 7x to 30x, organisms may be identified to a lower taxonomic level such as family or genus. Identifying specimens to the species level is sometimes difficult or impossible because, 1.) Immature specimens often differ widely from the appearance of mature specimens. 2.) Damaged specimens may be missing structures such as gills that are vital to identification. 3.) Some species have variable color patterns that may not be the same as the images in this key. 4.) Species identification keys are not available for some groups.
This key covers organisms collected with an aquatic kick net from riffle areas of streams with substrates consisting of rocks, gravel and sand. The relatively fast current and varied substrate provides habitat for a diverse community of macroinvertebrates to colonize. Organisms not found in stream riffles in New York State may not be included in this key.
