Command of the sea Great Britain accepted the principle in 1805; Russia, in 1824; and the United States (tacitly) in 1894. Many treaties, including the Treaty of Versailles, have dealt with the open seas, and currently the United Nations Convention on the Law of the Sea formalizes this freedom. Historically, many powers attempted to extend command of the sea into peacetime, imposing taxes or other restrictions on shipping using areas of open sea. For example, Venice claimed the Adriatic, and exacted a heavy toll from vessels navigating its northern waters. Genoa and France each claimed portions of the western Mediterranean. Denmark and Sweden claimed
Gulf of Mexico Island. The Gulf contains a hypoxic dead zone that runs by east-west along the Texas-Louisiana coastline. In July 2008, researchers reported that between 1985 and 2008, the area roughly doubled in size and now stretches from near Galveston, Texas, to near Venice, Louisiana. It is now about , nearly the record. Poor agricultural practices in the northern portion of the Gulf of Mexico have led to a tremendous increase of nitrogen and phosphorus in neighboring marine ecosystems, which has resulted in algae blooms and a lack of available oxygen. Occurrences of masculinization and estrogen suppression were observed as a result.