Starting in January, JetBlue will no longer offer year-round daily service from the Portland International Jetport to New York City.

The popular low-cost carrier will fly daily between Portland and John F. Kennedy International Airport only during the summer, the company said in a news release Tuesday.

“Portland is a customer-favorite destination and sees a strong surge in travel during the warmer months of the year,” it said. “In response to customer travel patterns and demand, JetBlue will focus on providing the airline’s award-winning service and a customer-friendly schedule during the summer travel season.”

JetBlue will stop service to Portland after Jan. 7. Jetport officials expect service to resume after Memorial Day.

“It is always a loss to lose some level of air service,” Paul Bradbury, the jetport director, said in an interview Tuesday.

He said the airport knew about the service change about 24 hours in advance of the public announcement.

“They will remain seasonal, it is not like they are going to entirely go away,” Bradbury said.

While JetBlue is a preferred carrier for many, over the last decade the airline lost almost half its market share – in terms of passengers – at the jetport, according to an analysis of airport passenger records.

JetBlue carried almost 293,000 passengers between New York and Portland in 2008, roughly 17 percent of the airport’s passenger volume. Last year, it carried a little over 175,000, or roughly 9 percent.

During the interceding years, legacy airlines such as Delta, American and United merged with older carriers and new carriers such as Southwest airlines made major inroads in the Portland market.

Last year, JetBlue carried the fewest number of passengers at the jetport. Of the 1.8 million passengers that traveled through the airport, American Airlines carried 29 percent, Delta Airlines 25 percent, United 20 percent and Southwest about 16 percent.

Bradbury said he was surprised at how competitive the Portland market has been. Big carriers like American have expanded nonstop  flights, and Frontier Airlines, an ultra-low cost carrier, started flights to Portland from Colorado, North Carolina and Florida’s Gulf Coast. Last year, Delta added a nonstop flight between Portland and JFK airport, putting pressure on the JetBlue route, Bradbury said.

“The past year has been unbelievably competitive,” he said.

JetBlue’s decision to partially pull out of the jetport is part of a broader reorganization of its national and international flight network that will add flights and expand service, mainly in the Northeast and Florida.

The move will make the airline “more relevant in its key markets” and is “key to achieving the airline’s margin commitments and delivering long-term value to its shareholders,” the company said. A JetBlue official did not respond to an email with additional questions about the company’s decision to suspend year-long daily service in Portland.

About two-thirds of new routes will be added in Boston and Fort Lauderdale, Florida, JetBlue said. It is canceling service from the Daytona Beach Airport in Florida, a Puerto Rico-to-St. Croix, U.S. Virgin Islands, service and daily flights from New York and Boston to Dulles International Airport outside Washington, D.C.

The changes reflect part of a new corporate strategy aimed at improving profitability. JetBlue stock prices have dropped about 26 percent since the beginning of the year, and at a July earnings conference call executives said they were looking at reducing poorly performing flights in favor of expanding coast-to-coast routes this fall.

That JetBlue didn’t entirely cancel service to Portland shows how positive the market is, even though traffic is weighted heavily in the summertime, Bradbury said. Airlines are expected to add seat space for another 75,000 passengers to the jetport in the next six months, he said.

“We do have a seasonal component in our market which makes it difficult to plan when there is significant capacity coming online,” Bradbury said.

Even as JetBlue lowers its profile in the market, the three legacy carriers still will provide international connections for the state, he added.

“I’m always shocked that a metro statistical area with just over half a million people can connect us to the rest of the world,” he said. “Other small metro areas couldn’t imagine to have the level of service we have in Portland.”