Macroinvertebrates come in many different shapes and sizes. They can be short and fat, or long and skinny.
After you find the macroinvertebrates, separate them into the compartments of the ice cube trays. Compare the catch to the pictures in the field guides.
This is called the PTI, or Pollution Tolerance Index.
Give the macroinvertebrates values. The directions are found on the data sheet. Put tally marks by the macroinvertebrates you find. Next, use letter codes (A=1-9, B=10-99, C=100 or more) to record the number of organisms found.
Here is an example:
Add up the number of letters in each column and multiply by 3 in the sensitive column, by 2 in the somewhat sensitive column and by 1 in the tolerant column. This is called the index value. Here is an example:
Add the numbers in each column together to get the total index value. Put the number in the correct category - excellent, good, fair, or poor. This is the water quality rating.
Look at the data sheets!
We looked at many different data sheets, took all of the information we needed, and made our own data sheet. Take a look at the data.
Now, find out what the data means.
Fish and Aquatic Life: Aquatic Macroinvertebrates. Retrieved October 2006 from http://www.krisweb.com/aqualife/insect.htm .
Haddock, R. (2007, February 20 - April 2 ). Phone interviews and emails on benthic macroinvertebrates, water temperature, habitat quality, macroinvertebrate populations, identification of macroinvertebrates, condition of Caffee Creek.
Kristofik, E. (2007, September - April ). Personal interviews and emails on benthic macroinvertebrate monitoring, choosing a testing site, water pollution, identification of macroinvertebrates, equipment, refuge management, habitat quality.
Introduction to Benthic Macroinvertebrates. Retrieved November 2007 from http://kywater.org/ww/bugs/intro.htm .
Izaak Walton League of America. (1996). A Volunteer Monitor's Field Guide to Aquatic Macroinvertebrates. Gaithersburg, MD.
Izzak Walton League of America. Key to Macroinvertebrates. Retrieved
October 2006 from http://people.virginia.edu/~sos-iwla/Stream-Study/Key/MacroKeyIntro.HTML .
Izzak Walton League of America. The Stream Study. Retrieved
October 2006 from http://people.virginia.edu/~sos-iwla/Stream-Study/StreamStudyHomePage/StreamStudy.HTML .
Maryland Department of Natural Resources. Freshwater Benthic Macroinvertebrates. Retrieved December 2007 from http://www.dnr.state.md.us/streams/pubs/freshwater.html .
Owings, J. (2007, March 29) Personal interview on choosing a monitoring site and identification of macroinvertebrates.
U.S. Environmental Protection Agency. Macroinvertebrates in Our Waters.
Retrieved December 2007 from http://www.epa.gov/bioindicators/html/worms.html .