Trade in Nautilus spp., such as this N. belauensis from Palau, will now be regulated under CITES Appendix II. The curio/shell trade is mainly cited as the cause for population declines of Nautilids. Image by Manuae - CC BY-SA 3.0

https://creativecommons.org/licenses/by-sa/3.0/deed.en | https://en.wikipedia.org/wiki/Nautilus#/media/File:Nautilus_Palau.JPG