Citing a difficult economy, a drop in visitor arrivals, dwindling state grants and a poor return on investments, the Bishop Museum decided yesterday to close its main facility in Kalihi every Tuesday and shut down the Hawai'i Maritime Center at Aloha Tower.

The changes are to take effect on May 1.

The museum also will lay off and furlough an undisclosed number of staffers, said Blair Collis, museum chief operating officer and senior vice president. Collis would not say how many of the museum's 215 employees would be laid off or how much money the museum would save with the cuts.

This is the second time in less than a year that the museum has initiated budget trimming measures. In June, the museum laid off 14 people, or 6 percent of its staff.

"The economic downturn is affecting us as visitors are not coming, the cost of doing business has risen and there have been cuts in state funding," Collis said. "Mostly, it's because of the loss of some state funding and the stock market crash affecting our investment income."

Closing every Tuesday is an unprecedented move for the 120-year-old museum, which is recognized around the world as the primary repository of Polynesian artifacts and the premier Hawaiian research institution.

Until now, the museum has only closed on Christmas Day. Closing on Tuesdays makes sense as Tuesdays have the lowest attendance of the week, Collis said.

"It's understandably sad right now," he said. "We are disappointed that we can't do what we have been doing. Unfortunately, museums are not immune to the economy. We have to adjust so that the museum can sustain itself for the future. To do anything less would be irresponsible."

Museums across the country are making similar decisions, said Dewey Blanton, senior manager of media relations for the American Association of Museums based in Washington, D.C. Some have cut hours and exhibits and others have reduced staff.

"A lot of institutions are recording record attendance," Blanton said. "But attendance alone doesn't pay the bills, not entirely. It takes a combination of private donations, earned income from investments and some government funding."

Museums play a vital role in a community, Blanton said. They're the keeper of a community's culture and historic heritage.

Visitors Noriko and Masatoshi Kajiura were at the Aloha Tower yesterday when they saw the Falls of Clyde and decided to check out the center next door. They enjoyed the museum's self-guided tour in Japanese.

"I like to look at historic things," Noriko Kajiura said. "The translation is very good, but this is not very well advertised with the Japanese visitors."

On average, only about 40 to 48 visitors pay the $8.50 adult admission fee at the maritime museum each day, compared with 509 visitors daily at the main Bishop Museum.

The cuts will not affect the museum's plan to reopen its Hawaiian Hall in August. The hall has been closed since June 2006 for $16 million worth of renovations.