Received: 27-06-2019 / Accepted: 16-09-2019
A study ontheefficiency of hard clam farming in earthen ponds was conducted in Ben Tre and Nam Dinh provinces to assess the growth, survival rates,economic efficiency and food safety of farmed clamsin commercial production. Two earthen ponds (total areaof 1.8ha) in Ben Tre province and four earthen ponds (total area of 2.2 ha) in Nam Dinh province were used in thisstudy. The results showed that the growth rate of clamswas seasonally affected and it fluctuated in the range of 1.27-1.39 g/month. The survival rate of clams varied from 70.65 to 90.00% and there existeddifference in two study areas. The clamscultured in Ben Tre province had higher survival rate than those in Nam Dinh province. The harvested size varied from 48 to 55 individual/kg and the harvested clamsmet the standards of food hygiene and safety. The clam productivity in two areas ranged from 22.08 to 24.55 tonnes/ha/crop and the profit varied between19.86 million VND/ha to 26.86 million VND/ha and/crop. The marginalcost benefit ratioin Ben Tre (0.28) were higher than that in Nam Dinh (0.22). The results of the study confirmed the ability of the clam farming model in earthen pond in the coastal areasof Vietnam.