Stop the Spread of Invasive Mussels Act of 2023

This bill authorizes federal agencies (like the Bureau of Reclamation and National Park Service) to inspect and clean watercraft entering or leaving federal reservoirs and waterways in 18 western states (including California, Arizona, and Texas) to prevent invasive mussels from spreading. It creates a competitive grant program to help these states, tribes, and local groups set up and operate inspection stations, with the federal government covering up to 75% of costs. The law requires coordination with tribal nations and the Aquatic Nuisance Species Task Force, and allocates $25 million annually for these efforts starting in 2024. It directly affects boaters using federal waters in Reclamation States and state/local entities managing inspection sites.