US Fish and Wildlife Service (FWS) has delayed the full implementation of the FWS message set in the Automated Commercial Environment (ACE). The effective date was recently postponed to March 2021; however, the enforcement is now set for June 2021. According to CSMS 46044069, all filers currently have the option and are recommended to file FWS data in ACE now.
For more information, the FWS Implementation Guide and PGA Message Set samples are available on US Customs and Border Protection’s ACE Automated Broker Interface (ABI) and CBP and Trade Automated Interface Requirements (CATAIR) page.