So now, less than three weeks after its highly promoted opening on March 19, the Western Pacific Giant Clams exhibit has been closed to the public. Particularly significant is that the thieves selected the most stunning of the exhibit's 44 clams, which are a threatened species, aquarium director Andrew Rossiter said yesterday.

That suggests these thieves know their clams.

"We have no idea how it happened, whether it was a one-person job, or if someone was looking to see who was here while someone else was picking them out."

Rossiter said the exhibit's remaining 37 clams have been moved inside and will remain out of public view until the aquarium devises a new and safer means of exhibiting them.

"The exhibit, which is the only one of its kind in the whole of America, was built at a low level, especially so that children could have access to it," Rossiter said. "Now, they're denied that possibility."

Rossiter, who said the theft is a federal crime, asked whoever has the clams to return them — "No questions asked, a complete amnesty.

"So please think carefully, look deep into your conscience, and please bring them back."

Should the thieves ignore the amnesty, he said they face up to $200,000 in fines and three years in prison.

Rossiter said the clams were to be part of the aquarium's captive breeding program, intended to help restock the threatened species in the wild. He said the theft had been a setback for that program.

The stolen clams are smaller cousins of the 250-pound Tridacna gigas on display in the aquarium's Gallery One — the largest such creature in captivity.

The clams that were taken were juveniles, and ranged in length from 1 to 4 inches. They do not exist in Hawaiian waters, and could die quickly if not properly cared for.

The attraction of the stolen clams, which reach a total length of no more than 18 inches, is not their size but their breathtaking iridescent emerald green, sapphire blue and orange topaz colors.

Rossiter said he believes the clams were targeted because of their rarity and beauty.

Frank Gornichec, owner of Modern Pet Center in Honolulu, said on the black market such exotic clams could bring between $300 to $500 each, and that such illegal dealings are not uncommon.

"I can't believe someone stole them," Gornichec said. "Apparently, they knew exactly what they were looking for."

Randy Fernley, owner of Coral Fish Hawai'i in 'Aiea, said it would be nearly impossible for thieves to sell the giant clams locally because any legitimate dealer would know immediately the clams were hot.

"If I find anyone who has them, I'd be sure to contact the aquarium," he said. "I would never sell anything like that because it would be illegal."

Rossiter said it could be six weeks or more before the exhibit reopens, and even then, the spectacular colors of the giant clams would not be as visible as before.

That bothered many of the aquarium staff.

"We try to build exhibits that get the people as close to nature as we possibly can," said curator Gerald Crow. "And it's very frustrating to put in all that work and let people get that close to them, and then to have somebody steal them. It's a deep disappointment."