Marine Disease Emergency Act of 2014 - Authorizes the National Oceanic and Atmospheric Administration (NOAA) to declare and respond to a marine disease emergency (an event that affects the marine environment, is caused by a marine disease or environmental stressor, is likely to threaten the sustainability of a marine species or the health of a marine ecosystem, and is likely to expand in geographic scope).

Requires NOAA to designate an individual to coordinate the response to each emergency and develop and publish a response plan for each emergency within 21 days of the declaration.

Terminates the emergency when NOAA declares that the emergency no longer exists or 120 days after the declaration was made, whichever occurs first. Authorizes NOAA to renew a declaration.

Establishes the Marine Disease Emergency Working Group in NOAA to provide advice on assessing, declaring, and responding to those emergencies.

Establishes the Marine Disease Emergency Fund for responding to those emergencies.

Requires NOAA to establish a National Data Repository for Marine Diseases Research and Services to collect, store, and disseminate information on marine diseases and related data and facilitate the development and rapid dissemination of research on marine diseases.

Deems sea star wasting syndrome, a marine mortality event affecting species of sea stars, to be a marine disease emergency.