The family of 24-year-old Keion Jamir Dade has been searching the waters off Long Beach daily since he went missing on June 10.
Dade was reported to have fallen off the Jet Cat Express about three miles off the coast as the high-speed catamaran headed to Santa Catalina Island, authorities said.
Crews with the Los Angeles County Fire Department and U.S. Coast Guard, along with the Los Angeles County Sheriff's Department, searched throughout the night. By the next day, the Coast Guard called off the effort "pending further updates" after combing through more than 600 square miles.
The Orange County Register says the Coast Guard told the family the currents likely swept Dade from where he was last seen.
They are now calling on the agency to resume its search and asked any divers and pilots to help.