the Saint Lawrence Seaway Development Corporation, $40,000,000, to be derived from the Harbor Maintenance Trust Fund, pursuant to Public Law 99–662 : Provided , That of the amounts made available under this heading, not less than $16,000,000 shall be used on capital asset renewal activities. Maritime administration Maritime security program For necessary expenses to maintain and preserve a U.S.-flag merchant fleet to serve the national security needs of the United States, $300,000,000, to remain available until expended. Operations and training (Including transfer of funds) For necessary expenses of operations and training activities authorized by law, $154,442,000: Provided, That of the sums appropriated under this heading— (1) $77,944,000 shall remain available until September 30, 2021 for the operations of the United States Merchant Marine Academy