Sea ducks, like other migratory birds, are governed and protected by the Migratory Bird Treaty Act of 1918, a treaty recognized by the United States, Canada, Mexico, Japan and Russia.
The conservationists, scientists and political leaders who drafted and enacted the MBTA had incredible foresight that stands the test of time. The treaty allows for hunting of sea ducks and other migratory birds when regulations governing things such as bag limits, equipment, techniques and seasons are made based on "due regard to the zones of temperature and to the distribution, abundance, economic value, breeding habits, and times of migratory flight." (16 U.S.C. 704)
Many of the resources on this site are categorized using these farsighted considerations developed early last century.