National and international laws are in placed to protect the giant clams. Most of the laws are made to discourage people’s antisocial behaviour towards the giant clams, for example, poaching. This would then possibly help tackle the issue of declining giant clams population.
Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agreement between governments to voluntarily bind themselves to CITES. Animals listed under CITES are prohibited from being imported to and exported from these member countries unless an authorised permit is presented. As we know, giant clams are listed in Appendix II of CITES, hence there is a prohibition on the import and export of them.
Members of CITES have to impose their own national laws to complement CITES as well. For example: 
Laws seem to be a good way to stop negative behaviours towards giant clams, but firm and consistent enforcement need to be present to ensure that laws are abided by. Many times, due to the slack in enforcement, laws are not abided by the people and illegal poaching gets away scot-free.