Two of the most promising mine countermeasures (MSM) systems in the U. S. Navy's inventory are the Remote Minehunting Operational Prototype (RMOP) and the Marine Mammal (dolphin) System. The EMOP was developed at Coastal systems Station of Naval Surface Warfare Center, Dahlgren Division. The MMS dolphins are normally housed in open-water enclosures and work untethered in the open ocean. Although free to swim away and join wild dolphins, these Navy mine hunters choose to stay and work with their handlers and have proved extremely reliable since first introduction to the Navy in the early 1970s. Exact Date Shot Unknown