Procedures for Collecting Macroinvertebrates

The purpose in collecting the macroivertebrates is to find the different types of macroinvertebrates and their water tolerability. The procedures are as follows:

1) Construct a kick net- a large seine-like net held together on two ends by wooden poles.

2) Find a place in the water where debri is present. The probability of collecting macroinvertebrates will be greater in these areas.

3) Wade out to the chosen area but walk lightly as to not disturb the environment.

4) Having two people hold each side of the net, submerse the net into the water at a 45 degree angle with the bottom of the net tightly against the bottom of the stream, so no organisms can escape. The net should be slanted following the current of the water. Do not allow water to flow over the top of the net.

5) When the net is in place, the third person needs to stand in front of the net, with the current flowing from behind them, and they need to try and dislodge all of the small microorganisms.

6) To do this, the student needs to kick the stream bottom in the direction of the net. Using his or her hands, the student needs to separate and shake each separate piece of debris in the direction of the net so that all the macroinvertebrates can be collected. Make sure the bottom of the net remains tightly held against the stream bottom at all times.

7) When the student has completely disturbed the entire environment around the net, the net will need to be removed from the water. The two students on either side of the net will need to reach down and firmly grip the bottom of the wooden poles that are against the stream bottom. Move the net upstream, against the current, in a scooping motion so that no organisms are lost. The pressure from the current will hold all organisms on the surface of the net.

8) With the net held horizontally, move to land and lay the net on the ground.

9) With tweezers and magnifying lenses, the students should search for and remove any macroinvertebrates in the net and place them in a water-filled container.

10) Repeat the procedure many times to collect the maximum number and variety of macroinvertebrates possible.

11) Once the students have collected the macroinvertebrates, place them into collection bottles containing ethyl alcohol and a drop of glycerin.

12) Return to the lab and using keys, sort and identify the macroinvertebrates into separate collection bottles.