The ranks of the Blue Dog Coalition thinned even more with Rep. Heath Shuler’s retirement announcement today, immediately calling the group’s future into question.

The once-mighty fiscally conservative group was a thorn in the side of Democratic leaders while the party was in the majority following the 2006 elections, but the Blue Dogs lost scores of members to the bruising 2010 midterms, a trend that will continue as a wave of retirements has hit them.

“Oh man, that’s a crushing blow to the institution, and it’s tough for the Blue Dogs,” said Rep. Kurt Schrader (Ore.), a Blue Dog Democrat who had not yet heard about Shuler’s announcement.

Shuler is just the latest in a string to announce retirements, but the North Carolina Democrat insisted the Blue Dogs would always have a place in the House.

“I feel very confident there’s going to be 20 others that take our place next year,” he said shortly after releasing his announcement, citing family reasons as the cause for his retirement.

After seeing their numbers halved after the midterm elections, many decided in the past year to hang it up, including Reps. Mike Ross (Ark.), Dan Boren (Okla.) and Dennis Cardoza (Calif.). Rep. Joe Donnelly (Ind.) is running for the Senate, and former Rep. Gabrielle Giffords (Ariz.) vacated her seat last week to continue her recovery after being shot in the head at a constituent event last year. Former Rep. Jane Harman (Calif.) stepped down last year to take a position as the head of the Woodrow Wilson Center.

Rep. Jim Matheson, who co-chairs the Blue Dog Coalition’s political action committee, said the news is not easy to take, but he said he remains optimistic the group will rebuild.

“I hate to see my friends go. Don’t let me sugarcoat this. But I think, in terms of the ideas behind the Blue Dogs, is what America wants. I think it’s still a very viable and credible organization,” the Utah Democrat said. “I see this as a bump in the road in terms of folks who may be leaving, but I also see an opportunity for Blue Dogs to fill a void that’s missing in Washington, D.C.”

The group has endorsed five candidates so far, and Matheson said more endorsement are on the way. The five candidates are Florida state Rep. Leonard Bembry, South Carolina state Rep. Ted Vick, Arkansas state Rep. Clark Hall, Iraq War veteran Brendan Mullen in Indiana and Assistant U.S. Attorney Rob Wallace in Oklahoma.

The recruiting class gave Rep. Sanford Bishop cause to believe the ranks will be replenished.

“The elections haven’t even been held yet,” the Georgia Blue Dog Democrat said. “We’ve got a strong recruiting class, and there are some very good prospects that probably will even up the numbers that we’re losing.”

Democrats have been bullish about their chances of winning at least 25 seats to win back the House majority, and that goal requires them to win in swing districts like those represented by Blue Dogs. As far as Shuler’s seat, redistricting saddled him with an overwhelmingly Republican district.

“It makes it a little bit more difficult to retain the seat,” Democratic Caucus Chairman John Larson (Conn.) said. “We’ve got our work cut out for us, and we have had for some time, but we think there are several paths to the majority.”

Democratic Congressional Campaign Committee Chairman Steve Israel, a one-time Blue Dog member, denied that the party’s goal is any harder with Shuler and other fiscally conservative Democrats opting to leave Congress.

“When we laid out our strategic plan to win 25 seats, we took into consideration the hill would be a little higher in places like North Carolina for us and much higher in areas like Illinois, California and elsewhere” for Republicans, Israel said.

Israel said there would still be a place for Blue Dogs in the Democratic Caucus, despite their thinning ranks. In a statement, Ross, like Shuler a co-chairman of the group who is retiring this year, also vowed the coalition would live on.

“The Blue Dog Coalition will continue to follow his example of leadership and work hard to bring both parties together to solve the fiscal challenges that face this nation,” he said.

Shuler passed on running for governor in the Tar Heel State, and his name was floated as a potential athletic director candidate at the University of Tennessee, his alma mater and where he was the starting quarterback on the football team. Shuler said he told Democratic leaders today of his decision after weeks of consideration, during which some colleagues tried to talk him into staying.

“This is not a surprise to any of them,” he said.

Minority Leader Nancy Pelosi, whom Shuler unsuccessfully challenged for Democratic leader last year, said Shuler “has been a national leader for fiscal responsibility who has always maintained a laserlike focus on his constituents in western North Carolina.”

“Congressman Shuler will be missed by his colleagues on both sides of the aisle,” the California Democrat said in a statement. “We wish him the best in his next steps.”