Results of a silver carp spawning suitability model for the Olifants River, July 1, 2017-June 30, 2018 A growing degree days (base 15). 633 GDD15 (red dashed line and solid red vertical line) is required for maturation and 900 GDD15 (blue dashed line and solid blue vertical line) is required for initiation of mass spawning B mean daily water temperate. Minimum temperature required (red dashed line) is always exceeded C unimpeded river length required for egg hatching to occur D mean daily water velocity. Flow spike required for high suitability is not achieved.