Fish

Fish play a vital role in helping us assess the health of streams. By studying fish communities over time, scientists can learn a lot about the past and present state of streams. For example, too much sediment and pollution can harm sensitive fish species and cause physical problems for fish. Their presence and behavior act as important indicators of stream health, providing valuable insights about the health of the stream and its chemical, physical, and biological conditions. In Montgomery County, we classify fish into three groups based on how well they can live in different types of water:

  • Highly Sensitive fish are only able to survive in the county's highest quality streams.
  • Sensitive fish can survive and sometimes thrive in areas that receive minor pollution.
  • Pollution Tolerant fish live in most streams in the county, but they are the only fish that can survive in heavily polluted waters.

Highly Sensitive

Brown Trout Brown Trout
Blue Ridge Sculpin Blue Ridge Sculpin
Northern Hogsucker Northern Hogsucker

Sensitive

American Eel American Eel
Greenside Darter Greenside Darter
Longnose Dace Longnose Dace
Rock Bass Rock Bass
Rosyside Dace Rosyside Dace
Yellow Bullhead Yellow Bullhead

Tolerant

Blacknose Dace Blacknose Dace
Brown Bullhead Brown Bullhead
Creek Chub Creek Chub
Green Sunfish Green Sunfish
White Sucker White Sucker

Monitoring Fish

The Department of Environmental Protection utilizes electrofishing to study the diversity, population size, and health of fish in streams. Electrofishing involves the use of a small electrical current to temporarily stun the fish, allowing DEP biologists to capture and examine them. Once identified and studied, the fish are safely released back into their natural environment, contributing to our understanding of stream ecosystems.

Fish Identification

Electrofishing

Data Request

Interested in DEP monitoring data?
Contact DEP at AskDEP@MontgomeryCountyMD.gov to request the various data sets the County collects, including our fish data.