Search crews dragged fishing nets along the Sandusky Bay shoreline east from Crystal Rock, north about 4000 feet along the Edison bridge then back west forming a horseshoe shape.
But the nets were empty when crews hauled them in at about 1 p.m.
Cadaver-sniffing dogs were still combing the bay at about 1:30 p.m. and one dog indicated to a spot not covered by the nets.
See more photos of the search HERE
Divers are searching the area.
Jonathan Francis, 30, and his daughter Viola, 12, were last seen Saturday evening paddling toward the Edison Bridge.
Their empty kayaks were discovered washed up along the Ottawa County shoreline near LIghtner Road on Sunday morning.