The dead whales, which were discovered Sunday, likely came from a larger pod of about 51 whales that were found stranded last week along the Gulf coast of Everglades National Park, the National Oceanic and Atmospheric Association said.
"We think these are from the same group," said Blair Mase, stranding coordinator for NOAA Fisheries. "We expected this would happen."
Of that original pod of 51 whales, 22 are now known to be dead, assuming the group found Sunday was from the larger pod, the South Florida Sun Sentinel reported.
The pod of pilot whales have been a subject of an extensive rescue campaign in which boats and helicopters from various state federal and local agencies, and nonprofit groups have attempted the keep the whales from beaching themselves.
Normally, pilot whales swim in very deep water, as deep as 1,000 feet.
Experts said the pod was no longer swimming and diving as a healthy group would but was moving slowly and in a disorganized fashion, suggesting illness, fatigue, malnutrition and dehydration are setting in.