National Oceanic and Atmospheric Administration Sexual Harassment and Assault Prevention Improvements Act of 2020 This bill addresses sexual harassment and sexual assault involving personnel of the National Oceanic and Atmospheric Administration (NOAA). Specifically, the bill expands coverage of NOAA's sexual harassment prevention and response policy to include personnel such as observers and at-sea monitors, and voting members and executive and administrative staff of regional fishery management councils; directs NOAA to provide a mechanism for anonymous reports of sexual harassment to its Office of Inclusion and Civil Rights and sexual assault to its Workplace Violence Prevention and Response Program; requires NOAA to ensure that allegations of sexual assault and sexual harassment are investigated thoroughly and promptly; provides for a restricted reporting structure that allows survivors of sexual assault to receive services without triggering an investigative process; revises reporting requirements on sexual harassment, sexual assault, and equal opportunity employment; and removes the requirements that acts of assault, resistance, opposition, intimidation, sexual harassment, bribery, or interference with a fishery observer be forcible in nature and occur on a vessel to be unlawful.