BioAssessment Saturday May 3rd

SimoneLipscomb (3)

Wolf Bay Watershed watch monitors water chemistry as a major indicator of “health” of the water.  Tests give us numbers that help us understand the condition of the waters.  Careful observation of the critters living in the water can also help.  Ospreys need clear water to fish.  Yellow-crowned Night Heron prefer muddy water–well, they prefer crayfish and the crayfish prefer muddy water.

For smaller streams and headwaters one really good indicator is the larvae of insects.  Several different insects develop under water feeding on algae or other larvae and they can be collected with dip nets.  Disturbing the bottom or growing plants can cause others to float with the current so that they can be collected in a fine mesh seine. By identifying the varieties and numbers of larvae and comparing that with known “profiles” we can get a good picture of the health of a particular stream.  Mayfly and Stonefly larvae only live in pure and clear waters.  Dragonfly or Cranefly larvae tolerate less favorable conditions.  Aquatic worms can survive just about anything.

A couple of volunteers with waders or hip boots will use fine mesh dip nets to collected from grass beds or other likely spots.  If we have a spot with good flow a fine mesh seine can be stretched across the stream and some volunteers can stir the grass and stream bottom upstream so that what floats free can be collected in the seine. collections are carried in buckets to an identification station.  At the ID station some volunteers separate the bugs from the water and debris in the buckets with screens or forceps and they are put in suitable separate containers (ice trays probably) to be counted. As soon as they are counted, they are returned to the water.

Members of each species are assigned a numerical “value” and the total in the “score” of the stream.

If you would like to participate please contact Homer Singleton.