Federal authorities have charged a Japanese citizen with smuggling after customs inspectors at Honolulu airport allegedly found 42 exotic turtles in his suitcase Monday.

Hiroki Uetsuki was arraigned in U.S. District Court Tuesday on charges that he tried to smuggle the turtles through customs after arriving on a flight from Japan, Assistant U.S. Attorney Thomas Brady said.

"The interception at the airport in Honolulu is due to the continued diligence of the inspectors," said George Phocas, U.S. Fish and Wildlife Service resident agent in charge. "It’s about protecting our environment."

Uetsuki allegedly tried to bring in three turtle species: the Indian star tortoise, white-fronted box turtle and fly river turtle.

The white-fronted box turtle has been restricted for private and commercial import to Hawaii and must be cleared with the state. All turtles or tortoises must also be approved by the state Department of Agriculture before they can be brought into the islands.

Although the species do not appear on the state’s prohibited species list, Phocas said they pose a threat to native Hawaiian species, including freshwater shrimp and fish.

"These things will attack native species," he said.

The Fish and Wildlife Service is looking after the turtles while the investigation continues.

The creatures were intercepted Monday by inspectors from Customs & Border Protection and the U.S. Fish and Wildlife Service.

Uetsuki is in federal custody and is scheduled to appear before U.S. Magistrate Judge Leslie Kobayashi next week to determine whether he can be released to Mahoney Hale, a Honolulu halfway house used as a pretrial detention facility.

Federal officials have not said why Uetsuki may have been smuggling the animals into the United States, but the species are popular in the exotic pet trade. Last year, wildlife trade monitoring network TRAFFIC reported that species of Asian box turtles had nearly vanished from the wild due to widespread smuggling operations.