Fig. 8. Farm yield (tonne/ha/crop) for (a) different provinces, (b) different regions (lower = Can Tho and Vinh Long, upper = An Giang and Don Thap), (c) water source (river or canal), (d) distance from Delta mouth (km), (e) age of farm (years), and (f) Feed type (C and F=both commercial and farm-made feed used