Graton Resort and Casino recorded $88.9 million in net revenue for the three months ending June 30, down 12 percent from its first-quarter results, according to a filing by Station Casinos, the Las Vegas firm that manages the gambling complex outside Rohnert Park.

In an early indication that income is not meeting the projections made before the casino’s November launch, profits from a portion of the casino’s 3,000 slot machines that fund guaranteed payments to the city of Rohnert Park and Sonoma County have fallen short, leading the Federated Indians of Graton Rancheria, which owns the casino, to dip into other revenue to make the quarterly payments, an attorney for the tribe said.

The casino reported $101 million in net revenue in its first quarter. The dip in second- quarter revenue could be due to a typically low season for the gaming industry or could be a result of the novelty wearing off since the $850 million casino opened Nov. 5, analysts said. Its net revenues include profits from gambling on slot machines and 144 card tables as well as food and beverage revenues at the 340,000-square-foot casino.

“Gaming, like many industries, is seasonal,” said Ken Adams, a strategic analyst with Las Vegas-based CDC Consulting. “It is best to wait for year-over-year comparisons to draw any major conclusions. There might be a ‘Ho hum, it isn’t new any more’ effect, but in my opinion it is too soon to know.”

A market assessment done in 2012 for Station Casinos projected total annual gaming revenue at $487 million in 2015 and $532.6 million by 2016.

Graton Rancheria has agreed to pay $8 million per year to Rohnert Park and $5 million per year to Sonoma County to offset the impacts of the casino on crime, traffic and other municipal services. Those payments are supposed to come from 15 percent of the profits on all slot machines, which the tribe pays into a state-administered fund.

Additional profits beyond those guaranteed to the city and county are to be shared between the two government entities. However, the fund is insufficient to make even the guaranteed payments, Graton attorney John Maier said.

“The projections were overly optimistic, and the fund is less than anticipated,” he said. “Slot machine revenue was not what it was projected to be. The tribe will continue to make its payments regardless of the Graton Mitigation Fund.”

Maier declined to state the fund’s balance, saying he was not authorized to disclose the information.

City Manager Darren Jenkins said Rohnert Park is not expecting to receive payments beyond those guaranteed to the city.

“We’re getting the guaranteed funds. It’s the nonguaranteed funds that are not going to be there,” he said. “We understood from the get-go that nonguaranteed payments in the first seven years would be unlikely.”

Tribal Chairman Greg Sarris said he was pleased with the second-quarter results. “What makes me the most happy is that the tribe is in a position to pay off its debt, to pay the money owed to the city and county, and that employees in the county have good jobs,” he said.

Graton’s debt includes a $375 million senior secured-term loan, due in 2018, and $450 million in senior secured notes, due in 2019. The tribe borrowed the money to build the casino.

Indian casinos are not required to make their earnings public. Station Casinos has publicly held debt and is required to file with the U.S. Securities and Exchange Commission.

In the Aug. 12 filing, Station Casinos reported that Graton had adjusted earnings of $53.8 million in the second quarter, a figure that excludes management fees, non-cash expenses, financing costs and other nonoperational or nonrecurring items. Graton paid Station Casinos $6.7 million in management fees, the statement said.

Analysts pointed to a nearly 60 percent profit margin as a sign of Graton’s strong opening. In a research note written June 19, before the release of the second-quarter numbers, financial services company Credit Suisse said the casino is “easily one of the most profitable and highest-margin regional gaming operations.”

“Given an easily accessible location and deep feeder markets, Graton has put up big numbers out of the box,” the report said. “Graton is driving a significant amount of its business from the Asian gaming segment. ... In addition to Asian gaming play, management described spillover demand from Wine Country and wealthy tech industry clientele.”