During the late 1970s and early 1980s, Vietnam was faced with difficulties for economic development. Among those difficulties were a critical lack of knowledge and expertise in aquaculture. In the Mekong Delta traditional aquaculture used the tidal differences to stock ponds with wild seed taken in with freshwater, brackishwater or seawater from the Mekong River. The indigenous freshwater prawn Macrobrachium rosenbergii was designated as a target species because of its high potential for the export market and several years were required before local institutions were able to master hatchery techniques. However, the difficulty of importing expensive Artemia cysts became the main bottleneck for further expansion of prawn farming in the Mekong Delta and elsewhere in Vietnam.