SALEM – U.S. Rep. John Tierney stunned his supporters at the Hawthorne Hotel early Tuesday night, announcing that he had chosen to concede to Democratic challenger Seth Moulton.Only 26 percent of the precincts in the 6th Congressional District had reported when Tierney took the podium at 9:20 p.m., but Moulton held an 11 percent advantage at the time of Tierney’s concession.Emotions flooded the hotel’s Sophia Room as the congressman departed. Supporters wearing white Team Tierney T-shirts shook hands and embraced each other as phrases like “tough night” and “sad to see him go” shot around the room.”We did a lot of work,” Tierney said of his nine terms in Washington, adding that his time in office was the “greatest privilege and honor of my life.”He told supporters that he was proud of the things he has done for the Bay State.Tierney reminded them that since taking office in the mid-1990s, he’s helped blunt the increasing cost of college, health care rebates have become available and the Bedford Veterans Administration Medical Center has remained open.”It was always a collaborative effort,” said Tierney. “This was an amazing 18 years.”Tierney Campaign Finance Chairman Barry Weiner, however, explained that after nine elections, Tierney’s advisers could accurately predict the inevitable.”We could tell what the trend was across the district,” said Weiner.Jeff Scuteri of Hamilton said that although it was a gutwrenching decision, Tierney made the right choice in conceding to Moulton.”John is a stand-up guy,” said Scuteri.His wife, Jennifer, clerk of the Hamilton Board of Selectmen, said that the communities of the 6th District will be losing a great congressman.