LEWISTON — After months of increasingly acrimonious negotiations, the Portland Pirates on Thursday said they’re packing up and moving to Lewiston, at least through the end of the 2013-14 American Hockey League season.

The decision leaves Pirates fans from Greater Portland facing a 40-mile ride to see their hockey team and will cost the Pirates some sponsorship revenue. But a majority of the Androscoggin Bank Colisee in Lewiston is owned by Ron Cain, who also owns 40 percent of the Pirates, offsetting some of the sting of moving the team to a smaller arena and market and ensuring a cozy landlord-tenant arrangement.

The move also leaves the newly renovated Cumberland County Civic Center in Portland without a lead tenant, barely four months before it is due to re-open after a $34 million upgrade, with many of the new amenities aimed at hockey fans.

After a court-imposed silence for much of September, the two sides took off the gloves Thursday after the move was announced.

Brian Petrovek, the managing owner of the team, said Pirates fans should be “outraged” by the “ill-timed, protracted” negotiations with the trustees of the publicly owned Cumberland County Civic Center in Portland, where the Pirates have played home games for most of their history, but were unable to reach an agreement on a new lease for the upcoming season.

Those talks culminated in a proposal that, he said, would have stripped the team of its value.

The head of the trustees fired back in terms that underscored just how heated negotiations had become.

“It’s very unfortunate that the Pirates, on their way out of town, chose to take shots at the Civic Center’s trustees after months and months of negotiations and results that they had control over,” said Neal Pratt, who argued that the arena would have lost money if trustees had accepted the team’s terms.

“The Pirates’ wounds are self-inflicted and they were made very knowingly by very smart business people and lawyers. The situation they find themselves in is a direct result of their own decision-making,” Pratt said.

This wasn’t the first time the Civic Center and Pirates have fought over the terms of the lease or came close to parting ways. In 2010, the Pirates welcomed courting by Albany, N.Y., which had just lost its AHL team, before finally coming to an agreement with the Civic Center.

But this time, the stakes were higher.

The Civic Center is in the final stages of the renovation, paid for by county taxpayers, that will add new luxury boxes, club seats and other amenities that trustees said were needed to keep the 36-year-old arena from becoming obsolete. The Pirates were supposed to return to Portland to play in the upgraded facility in January after playing home games during the first half of the season in Lewiston.

For the Pirates, those improvements provided an opportunity for the team to turn its first profit since Petrovek, Cain and Boston sports lawyer Lyman Bullard bought the team in 2000. The lease proposal had the revenue from sales of higher-priced suite, club and loge seat tickets going to the team, along with a share of concessions sales and a split of much of the advertising income.

Those stakes fostered brinksmanship in the negotiations that led finally to ultimatums, deadlines and the Pirates filing a lawsuit before the team decided to shift this year’s games to the 3,737-seat Colisee in Lewiston, which is about half the size of the Civic Center and considerably older, dating to 1958. Most famously, the arena — known at the time as the Central Maine Youth Center — was the site of the 1965 Muhammed Ali-Sonny Liston heavyweight championship rematch, resulting in the “phantom punch” than knocked out the favored Liston in the first round.

Petrovek, who said the lawsuit will continue, said the team’s future home will be dictated by its reception in Lewiston, the fate of the suit and whether there’s a change in stance from the Civic Center.

“We’ve always left the door open to the Cumberland County Civic Center and that’s not going to change,” he said Thursday at a news conference at the Colisee. “But as far as this season is concerned, we’ve just given you a commitment to play in this building, we’ve given you a commitment to embrace this community.”

Pratt said the Civic Center has been approached before by other teams and leagues, including hockey, when talks with the Pirates appeared stuck. He said the Civic Center will pursue those opportunities now.

And he said the Civic Center will seek to line up concerts and other events for the arena on dates left open by the Pirates departure. Civic Center officials who could provide information on how much income those events bring in couldn’t be reached Thursday, but Pratt said they can be lucrative, particularly compared to a goal of breaking even on Pirates games.

This year’s negotiations were complicated by the renovation, which meant the two sides couldn’t rely on past revenue and cost figures in their talks. Still, in April, both sides said they had reached a five-year lease deal with lower rent for the Pirates, who in return would take on a slightly larger share of the labor costs on game days. The two sides also agreed to share concession revenues, something Petrovek had eagerly sought in prior leases, and advertising revenue.

But the concessions revenue deal fell apart after state liquor officials said the Pirates couldn’t get a share of alcohol sales because they don’t hold the facility’s liquor license. Subsequent proposals by the Civic Center to offset the loss of that share were insufficient, Petrovek said.

Another issue involved “sub-naming rights” that would be sold for parts of the arena, such as the ice rink and new luxury suites. Petrovek said an agreement to split “above-the-ice” advertising revenue meant he would share in that money, but the Civic Center said it had retained all naming rights profits.

Pratt said there were other issues as well, but he said that while the Civic Center sought only to break even on the games, the Pirates wanted more.

“The demands that the Pirates were making these last few months were too rich” and would have amounted to a subsidy of the team by the taxpayers, he said.

After the two sides traded proposals over the summer, the Civic Center trustees drew a line in the sand and sent Petrovek a final offer in late August, giving him 48 hours to sign the lease. He refused and the next week filed a lawsuit against the trustees, asking a judge to enforce the terms of the April agreement.

Pratt said the April resolution passed by the trustees noted that further negotiations were needed and, in any case, no lease was ever signed.

He also that about an hour after that trustees meeting, he ran into Petrovek, who told him the Pirates would move ahead with selling season tickets for games at the Civic Center. Pratt said he warned Petrovek that the deal wasn’t complete and any decisions the Pirates made would be taken at the team’s own risk.

After Petrovek filed the suit earlier this month, a judge called both sides into a settlement conference, a private pre-trial stage intended to find a solution that avoids a court fight. But the only thing both sides agreed on was that effort failed this week, and Petrovek moved quickly to announce the shift to Lewiston.

Both the AHL and the Phoenix Coyotes, the Pirates parent team in the National Hockey League, took a mostly hands-off approach to the move.

Although the Coyotes have in the past hinted that they preferred Portland — and largely insisted on holding games at the Civic Center during a brief playoff run by the Pirates last spring — a team spokesman said Thursday that they were going to “move on” after Thursday’s decision to shift to Lewiston.

“Clearly, it is a disruption for us,” said Brad Treliving, the Coyotes’ assistant general manager. “But it’s the hand we’re dealt and we’re going to do the best we can with it.”

Dave Anderson, the commissioner of the AHL, said the league has no requirements about where teams play other than making sure the rink is of sufficient quality and safety for games.

“It honestly doesn’t come as a surprise,” Anderson said of the move and he noted that under league rules, the Pirates have a right to play anywhere within 50 miles of Portland.

But after a team history of more than three decades in Portland, “to see it come to this is disappointing,” Anderson said.

However, Lewiston fans said they were looking forward to having a top minor-league club in town.

“This community, most of it, is 100 percent hockey over anything else in sports,” said Norm Dubois, a 74-year-old resident of neighboring Auburn. “People will embrace it.”

As for disappointed fans who live in Portland, Cain said the team was forced into making a move.

“I feel bad for the fans in Portland,” he said, “but the trustees have drawn that line. I didn’t.”