It was based on the Japanese manga series written by Shuho Sato. Umizaru(?C??) means "Sea Monkey"; a derogatory label slapped on the rescue diver trainees by local townsfolk of the city due to their excessive and uninhibited behaviour during off hours.
The series focuses on Daisuke Senzaki, a future officer in the Japan Coast Guard, and tells the stories of shipwreck rescues and other incidents where the coast guard plays a role. The plotlines in the series were drawn from incidents and accidents which actually happened while the manga was being written.