Letters of Marque and Reprisal.[1] This is how the early U.S fought the Barbary pirates in the Barbary Wars[2] in the early days of the republic. This power is actually authorized explicitly in the U.S Constitution.
It would be better to fight the defacto slavery of the crews (agencies, owners and so on), the abysmal conditions in these crews home countries and sanction the hell out the owners of these ships and the people / companies making a healthy profit from them. But why bother, because you would just end up with more expensive shipping im general and more expensive fish.