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Maryland's Stream Life
Maryland has more than 16,000 miles of freshwater streams—an extensive system
of waterways flowing downstream where (depending on their geography) they
ultimately contribute freshwater to the Chesapeake Bay, the Atlantic Coastal
Bays, the Ohio River, or the Delaware River. The condition of these streams is
vitally important to downstream waters, but these streams also possess
significant inherent value.
The diversity of stream habitats throughout Maryland—from the cold mountain
streams of Western Maryland to the slow, dark swamps of the Eastern
Shore—supports an amazing faunal diversity. This includes nearly 100 fish
species, 16 native freshwater mussels, nine native crayfishes, eight stream
salamanders, and hundreds of different aquatic insects and other benthic
macroinvertebrates.
The Maryland Department of Natural Resources Maryland Biological Stream
Survey (MBSS) was initiated in 1995 to provide the information necessary to
evaluate the health of Maryland’s streams, to report on the diversity of life
and habitats within them, and to inform stream ecological restoration and
protection. The core of the MBSS consists of a statistical design that uses
randomly selected stream locations throughout Maryland to provide a
representative sample of overall stream health and biological diversity. In
addition, a network of relatively intact “Sentinel Sites” provides a reference
for comparing other streams and tracking variability in instream conditions due
to factors such as climate and weather. Sampling also takes place at specific
locations to evaluate specific management actions.
At each site, the MBSS collects data about fish, aquatic insects, and other
macroinvertebrates, freshwater mussels, crayfish, amphibians, reptiles, and
associated physical, chemical, and landscape information. The MBSS uses benthic
macroinvertebrate and fish indices of biological integrity, specifically
developed for Maryland streams with standard scientific methods, to assess
stream ecological condition (often referred to as stream health).
