Updated March 21 at 6:17 p.m.

Residents of the South Coast are bracing for the loss of their only bus service to Boston. DATTCO, the company that operates the routes, has announced it is going to shut down its bus line on April 16, which brings riders from Fall River, New Bedford, Fairhaven, Dartmouth and Taunton to South Station and Copley Square.

“This is a decision we have struggled with for several months as we looked at options to both reduce our operating costs and increase fares substantially,” DATTCO wrote in a statement Friday. “Unfortunately, we have not found a solution that would provide a cost-effective commute option while overcoming the deficit we have been experiencing for several years.”

While local officials are hoping for a stopgap in service before the new South Coast Commuter Rail starts late this year, the Massachusetts Department of Transportation says it doesn’t have the money to support the bus.

“As much as MassDOT would like to see the commuter service continue, it does not have an existing funding source to support these service operations and is unable to provide any assistance at this time,” MassDOT’s Judith Riley told GBH News in a statement Tuesday evening.

According to MassDOT, 30 to 60 riders take the bus every day.

New Bedford state Rep. Antonio Cabral said he was shocked to learn that the service was being terminated from a constituent — and not from DATTCO or the Massachusetts Department of Transportation.

“This is very important for my constituency,” Cabral said. “Obviously, this is the only way they can commute to Boston if they can’t get up there with their own car. It doesn't make sense. Right now, we have no alternative.”

The new South Coast Commuter Rail service will serve New Bedford and Fall River, but officials want assurance that there will be an alternative until then for those who can’t, or don’t want to, drive to Boston.

New Bedford Mayor Jon Mitchell said he was “troubled” by DATTCO’s decision to cancel service altogether, and with little warning, in a statement Tuesday.

“Residents are now scrambling for alternate transit options,” he said. “Equally inexcusable is DATTCO’s lack of any engagement with the City, which would have been open to discussions regarding the possible takeover of affected routes by another carrier in a way that provides for a seamless transition.”

Mitchell says he has reached out to Massachusetts’ Transportation Secretary Gina Fiandaca to find a solution.

Update: This story was updated to include a response from MassDOT.