The Army is helping thousands of migratory fish reproduce.
Officials at Fort George G. Meade unveiled a "fish ladder" yesterday that will allow ocean-going fish to swim upstream to their traditional spawning grounds for the first time in 50 years.
For five decades, schools of blueback herring, hickory shad and alewife have been thwarted by a dam, which the U.S. Army built across the Little Patuxent River to supply the Odenton base with water.
Army contractors built a specially engineered metal and concrete staircase this spring to help the fish cross the dam and continue their 2,000-mile journey from the Atlantic Ocean to the river's upper reaches.
The ladder opens 8 miles of the river, extending from Fort Meadeto Laurel to the fish.
"It frustrates their natural instincts to get (to the dam) and just have to stop," said James Peck, assistant secretary of the state Department of Natural Resources. "For the firsttime in 50 years,they are going upstream.
"These fish just have the natural instinct to go up to those areas where they've always spawned," Peck said. "They just have something programmed into them."
The Army and DNR, which coordinated the construction, celebrated the opening of the $185,000 ladder yesterday morning. But honored guests --namely, the fish -- stayed away.
Col. Ron Colon, Fort Meade's engineering director, said fish swarmed up the ladder when constructioncrews finished work more than a month ago. But officials delayed public announcement until this week, when the migration of the blueback herring was supposed to reach its peak. Blue herring spawn in late April and early May.
"The result of that was the fish had their own ceremony last month and have already moved on," Colon said.
DNR biologists began planning the fish ladder in 1988 as part of a Chesapeake Bay Agreement negotiated a year earlier between Maryland, Pennsylvania and Virginia. More than 1,000 miles of fish spawning areas on Chesapeake tributaries are blocked by dams, culverts and other obstructions.
"Having a healthy fish population is an indication of the success of the bay cleanup program and the water's quality," Peck said.
Jay O'Dell, DNR's director of fish passage programs, said the ladder is one of 27 fish passages under construction.
The ladder's wooden baffles, which slow water flow, and its slope are meant to attract the blueback herring and shad, O'Dell said.
Other species indigenous to the river -- including the whitesucker and catfish -- will use it as well, he said.
At the DNR's request, the Army installed an underwater observation window, from which scientists can monitor the number, size and species of fish using the ladder.
The department also stocked the spawning grounds with additional blueback herring, which will breed and return next year, as "a genetic implant."
The Army's dam, above Welch's Bridge on Route 198, "had the effect of cutting the life line of the species," O'Dell said. "These fish have significant recreational and commercial value to the Chesapeake Bay."