Final answer:
The FDA (option 2)is the main regulatory agency that oversees the safety of imported fish, ensuring they meet U.S. safety standards.
Step-by-step explanation:
The primary regulatory agency responsible for the safety of imported fish is the Food and Drug Administration (FDA). The FDA is a federal agency of the United States Department of Health and Human Services tasked with protecting and promoting public health through the regulation and supervision of food safety, including imported food products. The USFDA monitors imports, including imported fish, to ensure they meet the necessary safety standards for consumption in the United States.