The main purpose of this legislative text is to allow Congress to disapprove a specific rule that was put in place by the United States Fish and Wildlife Service. This rule concerns the Longfin Smelt, a fish species that is found in the San Francisco Bay-Delta area. The resolution aims to prevent the rule from having any legal effect, which means that the protections or designations that the rule would have provided for the Longfin Smelt will not be implemented.