The main purpose of this legislation is to modify the Marine Mammal Protection Act of 1972 to allow certain Indian Tribes to intentionally kill California sea lions and Steller sea lions in a specific area of the Columbia River. This change aims to help manage the population of these sea lions, which are believed to be impacting local fish populations, particularly salmon. Key provisions of the law include the authorization for designated Indian Tribes to carry out lethal takes of these sea lions without restrictions on the number or timing of the takes.