This legislation establishes the Great Lakes Mass Marking Program within the United States Fish and Wildlife Service. The program's core purpose is to mass mark hatchery-produced fish in the Great Lakes basin to assess the effectiveness of hatchery operations and various fisheries management actions. In carrying out the program, the Director of the U.S. Fish and Wildlife Service is authorized to purchase necessary equipment and hire additional personnel. Crucially, the Director must collaborate with applicable Federal, State, and Tribal fish management agencies, as well as the Council of Lake Committees of the Great Lakes Fishery Commission. The data collected through this program will be made available to relevant agencies to enhance understanding of management outcomes, assist in Great Lakes restoration objectives, and help balance predator and prey populations. This information is also intended to support and improve the economic status of Tribal, recreational, and commercial fisheries, and evaluate habitat restoration efforts. For the implementation of this program, $2,700,000 is authorized to be appropriated for each of fiscal years 2026 through 2030.