The Winnipeg mother disappeared after her two children were found critically injured in the bathtub at their home on Wednesday morning.
Police had been searching for Gibson, 32, in the area around the family's Westwood home until four teenagers taking part in a canoe race reported finding a body in the water by the Alexander Docks.
Her infant son and two-year-old daughter were rushed to hospital on Wednesday after being found in the family's home, but did not survive.
Gibson's family has asked for privacy.
More to come