Owners of jewellery containing a dorsal fin from a bowmouth guitarfish (Rhina ancylostoma), must report it to the authorities by November 29 or face a fine.
Items from the fish, which are on the Wildlife Protection List, require a permit or the owner risks a Bt40,000 fine, said Krabi Fisheries Office head Saen Sri-ngam.
The Ministry of Natural Resources and Environment's regulation added 12 aquatic species to the list in 2003 to prevent their extinction.
The 12 species were Mobula thurstoni, Mobula kuhlii, Mobula eregoodootenkee, Mobula japanica, Manta alfredi, Manta birostris, Himantura chaophraya, Rhina ancylostoma, Pristis zijsron, Anoxypristis cuspidata, Pristis pectinata, and Pristis pristis.
Among these 12 species, only Himantura chaophraya is granted the permission of commercial reproduction.