Sea of Marmara about 22 parts per thousand, which is slightly greater than that of the Black Sea, but only about two-thirds that of most oceans. The water is much more saline at the sea bottom, averaging salinities of around 38 parts per thousand, similar to that of the Mediterranean Sea. This high-density saline water, like that of the Black Sea, does not migrate to the surface. Water from the Susurluk, Biga (Granicus) and Gonen Rivers also reduces the salinity of the sea, though with less influence than on the Black Sea. With little land in Thrace draining southward, almost all of these
Custom of the sea Custom of the sea A custom of the sea is a custom that is said to be practiced by the officers and crew of ships and boats in the open sea, as distinguished from maritime law, which is a distinct and coherent body of law that governs maritime questions and offenses. Among these customs is the practice of cannibalism among shipwrecked survivors, by the drawing of lots to see who is to be killed and eaten so that the others might survive. After a whale rammed and sank the whaling ship "Essex" of Nantucket on 20 November 1820, the survivors