Zadar IV was the inhabited fourth planet of the Zadar system. This planet was the homeworld for a species of dolphins.

Prior to stardate 41509 , Starfleet oceanographer Lieutenant Harry Bernard, Sr. was stationed on Zadar IV with his son Harry Jr. They lived on the beach and Harry Jr. often saw dolphins playing in the ocean there. They were later the inspiration for his first attempt at sculpting. (TNG: "When The Bough Breaks")