Shrimp Poly-Culture Development and Local Livelihoods in Tam Giang-Cau Hai Lagoon, Vietnam

This research was conducted to evaluate the efficiency level of shrimp poly-culture farms by using Data Envelopment Analysis. It also identified factors affecting the inefficiencies of shrimp poly-culture farms using Tobit regression model. The empirical results indicated that the mean of Technical, Allocative and Economic Efficiency were at 84.01%, 64.16%, 55.32%, respectively, hence there is a substantial room for improving the efficiency. DEA results recommended that inefficient farms need to minimize overfeeding of stocks in order to avoid the accumulation of uneaten feeds that further contributes to water pollution. The optimal stocking density ratio should be 8.15 for shrimps, 1.59 for crabs and 2.46 for fish per square meter of pond. The results also showed the presence of scale inefficiency. Smaller farms tend to be more efficient than larger farms. The optimal farm size should be less than 0.5 hectares. The results of Tobit regression model suggested that farm personal characteristics, farm ability to access to institutions, and water environment have significant effect on the efficiency of farms.