According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), black corals are listed on Appendix II, which means that they are not threatened with extinction but their trade is regulated to avoid endangerment.
Additionally, in the United States, black corals are protected under the Lacey Act, which prohibits the importation, exportation, and interstate transportation of certain species of fish and wildlife if taken in violation of any law or regulation of a foreign country.
Mexico is a signatory to CITES, therefore the laws and regulations established by CITES are applicable to black coral specimens in the country.
Therefore, it is recommended to refrain from purchasing black corals when visiting Mexico to avoid any legal complications or potential penalties associated with the importation and possession of regulated or endangered species.