NMFS issues this interim final rule to revise regulations implementing the Dolphin Protection Consumer Information Act (DPCIA) to enhance the requirements for documentation that demonstrates the accuracy of dolphin-safe labels on tuna products. This interim final rule: Modifies the regulations (referred to hereafter as the "determination provisions") under which the NMFS Assistant Administrator (Assistant Administrator) may require proof of an observer certification if the Assistant Administrator determines that a fishery has a regular and significant association between dolphins and tuna and/or has a regular and significant mortality or serious injury of dolphins, to apply equally to purse seine and other gear-type tuna fisheries; provides that a government certificate validating the catch documentation, segregation, and chain of custody may be required for tuna produced from a fishery about which the Assistant Administrator has made a determination under the determination provisions; restructures NOAA regulations such that they now provide for one straightforward certification regarding intentional deployment and mortality/serious injury for all fisheries that produce tuna that is potentially eligible for the dolphin-safe label; modifies the Fisheries Certificate of Origin (FCO) to require captains to complete a training for certifications that must accompany the FCO; enhances chain of custody tracking requirements for tuna and tuna product; and makes several non-substantive modifications to the regulations. This interim final rule brings the United States into compliance with its obligations as a Member of the World Trade Organization (WTO).