Productivity of E. crassipes was recorded as 11-23 kgFW (fresh weight)/m2.year (0.5-1.2 kgDW (dry weight)/m2.year) during growing season in Japan, and reached 21.1 kgDW /m2.year under sufficient light and nutrients. Eel grass productivity is 0.3-0.8 kgDW/m2.year (120-320 gC/m2.year), and that of Thalassia reached 5 gDW/m2.day during 8 months in Florida, U. S.A.

Red alga, Hypnea, had productivity of 12-17gDW/m2.day in outdoor tank (Slesser and Lewis, 1973). Productivity of micro-algae is 2-10 gDW/m2.day in outdoor tank on average, and increases to 500 gDW/m2.day under the optimum condition.