A raceway, also known as a flow-through system, is an artificial channel on land. The water flows from a higher located point to a lower point and flows then back into the river or sea. In raceways there is good control of negative effects compared to open water systems. Several organic aquaculture certification programmes exist, the largest and most known is the German Naturland. Organic certification standards are very much alike: the feed needs to be organic and sustainable, only non-GMO organisms.