We observed this on farm D, which had thehighest COD levels and consistently displayed elevated DO duringtreatment. Elevated DO needs to be managed because prolongedexposure can result in fish mortalities (Pedersen et al., 2006). Acrossall SPC trials the DO peaked at 26.5 mg/L but reduced to normal(∼10.7 mg/L) within 60 min. Exposure to DO in this elevated rangefor this duration is unlikely to negatively affect rainbow trout(Edsall and Smith, 1990).