Investigators were trying to identify the boy, who was about 8 months old, find his parents and determine how he came to be in the water in Lower Manhattan, police said.
Her husband, Monte Campbell, who is a chiropractor, told the Times he called 911 and that when he was put on hold he decided to make sure it was a real baby and not a doll.
He was wearing only a diaper and was in shallow water near the Manhattan shoreline.
Police are investigating the death of a baby boy who was found floating in the Manhattan side of the East River on Sunday afternoon. The baby was later taken to a nearby hospital and pronounced dead, police said. "I called 911. At that point, I thought it was a doll", Monte Campbell said.
Authorities say an officer climbed over the safety railing and brought the unconscious child onto the walkway where officers attempted CPR.
He said the baby wasn't breathing and showed no pulse.
Police said the baby's body showed no signs of trauma.
"I spotted the baby. his little head was under the water. his little legs were over", Diana told CBS New York.
Austin's mom, Diane, was the first to spot the baby in the water shortly after 4 p.m. Both park-lined shorelines are usually teeming with tourists this time of year.