Can one international treaty help reverse years of rampant and widespread disregard for fisheries laws and policies? We believe the answer is yes, but a treaty is only as good as the parties that ratify and enforce it. The treaty in question is the Agreement on Port State Measures to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing, commonly called the Port State Measures Agreement, or the PSMA. Adopted in 2009 by the U.N. Food and Agriculture Organization, or FAO, the treaty requires parties to exert greater port controls on foreign-flagged vessels, and as a result to keep illegal, unreported, and unregulated, or IUU, fish out of the world's markets by removing the incentive for dishonest fishing operators to continue their illegal activities. But the PSMA will take effect only after 25 parties have ratified it. (For a current list of port States that have ratified the treaty.) Signatories to the PSMA should confirm their commitment to ending illegal fishing by ratifying, accepting, or approving the treaty now. Countries that did not sign the treaty can accede to it at anytime.