Importing Queen Conch shells from St. Maarten is allowed. From the U.S. Fish and Wildlife Service website, Queen Conch shells can only be imported from the following countries.

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Countries from which import may be allowed include: Anguilla, Aruba, Bahamas, Belize, Bermuda,
Brazil, British Virgin Islands, Cayman Islands, Colombia, Costa Rica, Grenada, Guadeloupe, Guatemala, Jamaica,
Mexico, Montserrat, the Netherlands Antilles, Nicaragua, Panama, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Turks and Caicos, and Venezuela