WASHINGTON (NNS) -- The Honorable Sean J. Stackley assumed the responsibilities of acting secretary of the Navy Jan. 20 at noon.

Stackley, who served as the assistant secretary of the Navy (Research, Development and Acquisition) for more than eight years, will carry out the day-to-day responsibilities of the secretary of the Navy until the incoming Trump administration nominates, and Congress confirms, a replacement for Secretary of the Navy Ray Mabus.

The Honorable Thomas W. Hicks, deputy undersecretary of the Navy (Management), will also perform the duties of under secretary of the Navy until a replacement for the Honorable Janine Davidson is nominated and confirmed.

The Honorable Allison F. Stiller will perform the duties of assistant secretary of the Navy (Research, Development and Acquisition). She previously served as principal civilian deputy assistant secretary of the Navy (Research, Development and Acquisition).

The Honorable Scott W. Lutterloh will serve as acting assistant secretary of the Navy (Manpower and Reserve Affairs). He previously served as the principal deputy assistant secretary of the Navy (Manpower and Reserve Affairs).

The Honorable Joseph B. Marshall will serve as the acting assistant secretary of the Navy (Financial Management & Comptroller). He previously served as the principal deputy assistant secretary of the Navy (Financial Management & Comptroller).

The Honorable Steven R. Iselin will serve as acting assistant secretary of the Navy (Energy, Installations and Environment). He previously served as principal deputy assistant secretary of the Navy (Energy, Installations and Environment).

The Honorable Anne M. Brennan will serve as acting general counsel of the Navy. She previously served as the principal deputy general counsel, Office of the General Counsel.