Stream Insects and Crustaceans for Healthy Water

The sampling of aquatic macroinvertebrates provides a convenient and cost-efficient method for determining the water quality of a stream.

Aquatic macroinvertebrates are water animals that have no backbone and can be seen without magnification.  Aquatic macroinvertebrates include such animals as crayfish, clams, aquatic snails, aquatic worms, and the aquatic larvae of winged insects.

Aquatic macroinvertebrates can be classified into three groups based on their ability to tolerate water pollution:

Pollution Sensitive: This group of macroinvertebrates are very sensitive to water pollution.  They are generally only found in water of good quality.

Stonefly Nymph
Caddisfly Larva
Water Penny
Riffle Beetle
Mayfly Nymph
Gilled Snail
Dobsonfly Larva
Water Flea
Planarian

 Somewhat Sensitive: This group of macroinvertebrates can tolerate low levels of water pollution.  They can be found in water of good or fair quality.

Crayfish
Sowbug
Scud
Alderfly Nymph
Fishfly Nymph
Damselfly Nymph
Watersnipe Fly Larva
Crane Fly Larva
Whirligig Beetle Larva
Dragonfly Nymph
Clam
Diving Beetle Larva

 Pollution Tolerant: This group of macroinvertebrates are tolerant of pollution.  They can be found in water of any quality.

Aquatic Worm
Midge Fly Larva
Blackfly Larva
Leech
Pouch Snail
Other Snails

© Diane Chase is the author of the Adirondack Family Activities™ guidebook series, Adirondack Family Time™, which is available online or bookstores/museums/sporting good stores. Diane is currently working on the third guidebook in the four-book series of Adirondack Family Activities™.