Hundreds of fish were found dead in the Anacostia River on May 25, 2014, after being trapped in a construction site near Hyattsville where contractors failed to adequately protect marine life. (Courtesy of Prince George’s County Government )

Maryland fined a CSX contractor after a construction project to expand a railroad bridge contributed to the deaths of hundreds of fish along the Northeast Branch of the Anacostia River in Prince George’s County, state officials said .

More than 600 gizzard shad and white perch were found dead and dying over Memorial Day weekend by people traveling the Northeast Branch Trail, a cycling and walking trail that runs along the river.

Shirley Contracting of Lorton, Va., agreed to pay a $12,350 penalty levied by the state Department of the Environment after an investigation determined that its construction project, near a Hyattsville neighborhood, violated several regulations and jeopardized marine life.

“The alleged violations involved regulations relating to erosion and sediment control,” agency spokesman Jay Apperson said in a statement. “They also included a failure to perform the required self-monitoring inspection following a rain event and subsequent high river flow, which led to a significant fish kill.”

Efforts to expand rail infrastructure in response to increased freight traffic have caused concern in communities such as the southeastern edge of Capitol Hill, where a CSX proposal to rebuild the Virginia Avenue tunnel has drawn opposition from residents.

Hundreds of Anacostia River fish were killed during the Memorial Day weekend after a construction company in Prince George’s County failed to comply with regulations. (Courtesy of Prince George’s County Government )

In the Hyattsville incident, CSX Transportation contracted with the construction company to broaden the railroad bridge to carry additional track, CSX spokesman Rob Doolittle said.

Workers erected cofferdams — temporary watertight structures designed to keep water out of the work site during the installation of concrete supports — and pumped the water out of the cofferdams, Doolittle said.

Rainstorms in late May caused river levels to rise and spill over the cofferdams and into the construction site, Apperson said. Some fish trapped by the cofferdams died when water evaporated and oxygen levels became depleted, he said.

Companies are required to inspect work sites and free fish caught in the structures, but several hours passed “before the contractor knew about” the situation, Doolittle said.

Nancy Meyer, a county resident, said she was riding her bicycle on the trail May 25 when she stopped to look down at the construction site and saw people walking around with shovels. “I could see it, and I could smell it,” she said. “It was a disturbing scene.”

She said she helped the group dig a channel for the fish to escape into the river. Some were saved, but many more died. Meyer later contacted Prince George’s officials and Shirley Construction about what had happened.

“The worst part is that it was spawning season,” Meyer said. “We were there for hours, catching and dumping families of catfish, several large and baby fish, into the river.”

As part of the settlement, Shirley Contracting will pay the fine with “no admissions of liability,” Apperson said. CSX, the permit holder, also has admitted no liability.

“We take our obligation to the environment seriously,” Doolittle said. “When we learn we are not in compliance, we take actions to correct it as soon as possible. We reviewed the contracting process to make sure this doesn’t happen again.”

Meyer, meanwhile, was satisfied that the site was cleaned up, but she expressed concern about CSX’s commitment to safeguarding the river as construction continues. “This is just an incredible resource, and I feel really strongly about the stewardship of this river,’ she said.