Unlike outdoor BFT pro-duction systems in the tropics that are operated year-round, the channel catfish studies were conducted only during the temperate-zone growing season and BFT production tanks were drained andidled at harvest. Operating the BFT system only during the growing season implies that at harvest the fish must be marketable or of a size appropriate for a subsequent stage of grow out. Other-wise, fish will be moved unnecessarily. Additionally, 4–6 weeks arerequired at spring start-up for a fully functional biofloc to develop