State officials and environmentalists cheered yesterday when they found 10 brook trout in the Jabez Branch, survivors of about 300 wild fish relocated in recent years to the shallow Severn River tributary.
"It's phenomenal, extraordinary," said Robert A. Bachman, director of the Fish, Heritage and Wildlife Administration of the Department of Natural Resources.
DNR biologists shot electric currents into the meandering creek between Gambrills and Severn on Monday to stun fish and bring them to the surface so that the biologists could assess their efforts to re-establish a wild brook trout population in the Jabez.
The creek was the last natural brook trout stream in the Maryland coastal plain and the southernmost wild native trout creek in the state before development harmed the creek and killed the trout.
"I'm going to drink champagne this evening," Lina Vlavianos, a member of the Severn River Commission, said Monday as she helped count and measure eight trout in the spring-fed left branch of the creek.
Last year, state officials found 24 of the wild trout, identifiable by clipped fins, that they had moved in 1991 and 1992 from other creeks in the state.
This year, they feared, they would find none.
"This is kind of a demonstration of the sensitivity of first-order streams," Mr. Bachman said. "What happens in these head-water streams affects the Chesapeake Bay."
What happened to Jabez Branch has happened to countless streams across the state: A vibrant wildlife population vanished with the arrival of development.
In the case of the Jabez, the development that did the damage was mostly roads. Construction of Interstate 97 and the upgrading of Route 32 and others led to warm-water runoff that killed the fish.
The surrounding woods and their spongy soils, which make up about half of the watershed, can absorb rapid cool rainfall from summer storms, Ken Yetman, a planner for DNR, explained in a 1991 study. But water that hits pavement heated to 130 degrees by the sun -- only 4 percent of the area -- rushes off into the stream, raising its temperature to 80 degrees, his study showed. Brook trout are cold water fish, and temperatures above about 70 degrees kill them.
The rush of water also scours the stream bed, depositing silt that smothers trout eggs, wiping away the nooks where trout hide from predators, and taking away the water insects that trout eat.
Researchers found 41 brook trout in 1986 -- before the road project began -- but the population declined rapidly until none were found in 1990, and the state planned its transplanting program.
In the late 1980s, local activists, biologists and environmentalists tried to save the Jabez's native trout population. The community organized cleanups along the banks. State highway engineers began installing better storm-water runoff controls along roads. DNR biologists made recommendations based on limited studies. But the small trout population vanished.
Since then, the State Highway Administration has redone much of its storm-water management for the area to restrict the flow of heated water into the creek. It plans to spend $180,000 to fortify the Jabez's severely eroded banks, using natural materials to help halt drainage of silt into the stream.
Yesterday, biologists found no young trout hatched in the Jabez, a disappointment, said Mr. Yetman. Yet they were optimistic.
The fish in the stream "could potentially have spawned last month," said Charlie Gougeon, a freshwater fisheries manager. The young hatch in March. A survey a year from now would turn up these fish.
Mr. Bachman said he advocates continuing to move, or transplant, wild trout to Jabez Branch. He pointed out that DNR stocked the Gunpowder River with brown and rainbow trout -- neither native to Maryland -- for more than 30 years for recreational fishing. In 1983, they began moving thousands of eggs, fingerlings and adult fish to the river, but it wasn't until years later that they began to reproduce.