Milwaukee County sheriff’s authorities say the diving team included a captain and four members.
The team member who died is identified as 53-year-old Susan Winn and the missing diver as her husband, 53-year-old James Winn, both of Kildeer, Illinois.
James Winn is presumed dead. The Milwaukee Journal Sentinel reports the U.S. Coast Guard said Saturday it was suspending the search.
The Coast Guard was called to the dive boat Friday about 17 miles from Milwaukee about a person who was unresponsive after surfacing. That diver later died, and the search began for a second diver.
The boat driver and two other divers were not hurt.