Creek Macroinvertebrates

Green DarnerAbout 5 miles of the Ballenger Creek flows parallel to the trail through sunny, wooded, shallow, and rocky areas.

Within the creek, lives a world of small animals without backbones called macroinvertebrates.

These “macros” are visible to the eye and live on rocks, logs, leaves, underwater plants or in the soft sediments of the creek. They include aquatic worms, crayfish, clams and snails, and aquatic insects such as mayflies, stoneflies, caddisflies, hellgrammites, and dragonflies.

The presence and/or absence of many of these animals tells us the water quality and overall health of the creek. 

This very diverse group of animals have a wide range of tolerance to different pollutants. For example, many mayflies, stoneflies, and caddisflies are generally sensitive to water quality and the physical condition of the stream. They often are the first to disappear in a stream polluted or degraded in some way. Below is a visual guide to the some common macroinvertebrates that you might see.

Quick Visual Guide to MacroInvertebrates: Use these photos for a quick reference. Click on the this link to access additional information these macroinvertebrates and where to look for them in the streams where they live:

Sensitive to Pollution:  Need very clean, usually cool water to thrive.

Links to Other References:

Stream Invertebrates: dnr bug sheet-UPDATED2015.cdr (

The Crayfishes of Maryland

The Salamanders of Maryland

Maryland's Frogs and Toads (Order Anura)

Stream Waders ( 

Frederick County Watershed Maps:

Catoctin_md_river_map.png (1500×1757) (

Catoctin-Creek-Fact-Sheet-2011 (