UPPER MARLBORO – The line of six men swept small metal hoops through the murky waters of Western Branch, sending an electric current from beeping packs on their backs across the stream Tuesday.
A twitching, snakelike brook lamprey floated to the surface and was quickly scooped up in a net and dropped into a bucket, where it would swim around unharmed before being released.
The brook lamprey is a rare species, precisely what the fish-shocking biologists with the Maryland Department of Natural Resources were looking for in Watkins Regional Park.
Each year, the biologists fan out to 250 stream sites around Maryland to count the aquatic life that indicate stream quality. The data is used to make recommendations to local governments on watersheds that the biologists say are critical to the well-being of the Chesapeake Bay.
“Streams are like capillaries forming larger arteries that end up in the bay,” said Ron Klauda, director of DNR resource assessment services.
Healthy streams provide a vital service by trapping sediments and processing nutrients and chemicals that would otherwise end up in the Chesapeake, Klauda said.
Western Branch is an example of a “stronghold watershed,” one of 84 stream systems in the state noted for their biodiversity and rare species. The wooded creek, less than 5 miles from the Capital Beltway, is one of only two Maryland waterways where the endangered stripeback darter fish lives.
“Things that live in streams are the most threatened organisms in the United States and in Maryland,” said Scott Stranko, a DNR biologist. Almost 10 percent of fish species once living in Maryland are no longer found here, Stranko said.
A top enemy of streams and streamlife is the increase of impervious surfaces like parking lots and roadways, which leads to runoff, erosion and life-killing water temperatures in the summer.
Maintaining buffers of green land along streams like the 850-acre Watkins Regional Park is crucial, Stranko said.
Since 1994, the Maryland Biological Stream Survey has collected and compiled data, using random stream sampling to monitor the quality of waterways across the state. The findings are used in land-use recommendations to county officials and state programs like Open Space and Rural Legacy.
In Prince George’s County, stream survey recommendations contributed to the Green Infrastructure Plan, designed to protect environmentally significant areas in the county.
On a stretch of nearby Collington Branch, the other home for the stripeback darter, developers hope to mitigate the impact of a planned development with new techniques to control runoff, like wider strips of forest along the water, Stranko said.
The stream survey program will determine how effective these techniques are.
Stream survey data is supplemented by about 800 volunteers across the state, the Maryland Stream Waders. Once trained, the volunteers arm themselves with nets to search for aquatic invertebrates in streams near their homes, then send the findings to state biologists who analyze and record their discoveries.
The volunteers look for underwater life like the dragonfly larvae, a carnivorous armor-plated insect shaped like a small brown leaf with spindly legs. The presence or absence of these creatures can indicate the overall health of a stream.
“People want to know, are there fish in the stream, can my kids play in the water?” said Takoma Park volunteer Chris Victoria before scooping a net under some tree roots hanging into Western Branch.
“This is the only program that comprehensively provides that information,” he said. “The purpose is all about restoring streams and biological communities.”
The biologists and volunteers hope that in addition to monitoring the health of the state’s 10,000 stream miles, the program can ultimately save some of Maryland’s disappearing aquatic habitats.
“The strongholds are only there because they aren’t being developed,” Klauda said. “We ask ourselves if we can get a handle on things before it’s too late.”