I recently read the book Unbroken, about Navy fliers in a raft for 43 days. They caught sharks but only ate the liver; they'd heard that sharks were inedible. One of the guys starved to death and the other two barely made it. Apparently the Navy didn't spend much time teaching survival to Navy fliers in those days. This was in 1943, a year after three fliers survived 34 days in a life raft with almost nothing, and a popular book about them was printed very quickly for public consumption. The book Unbroken stated that only 13 percent of U.S. fliers in the Pacific were ever rescued----there was just too much water out there for searching.