SAN FRANCISCO – More than two weeks after they were first spotted far up the Sacramento River, two lost humpback whales appeared to have finally found their way home Wednesday.
Officials said they assumed the pair returned to the open sea, undoing a wrong turn that drew thousands of admirers and a flurry of rescue efforts.
The unpredictable duo, believed to be a mother and calf, were last seen at sunset Tuesday less than 10 miles from the Golden Gate Bridge. The convoy of boats that accompanied them across the bay to keep traffic at a distance abandoned their escort service when it got dark.
Officials believe the whales slipped out of San Francisco Bay to the open sea late Tuesday night or early Wednesday morning, when no one was watching.
To make sure the whales did not take another wrong turn, two government boats were launched Wednesday morning to look for them in the Pacific Ocean, officials said. Rescuers planned to rely on reports from commercial vessels and Coast Guard patrols to determine if the humpbacks still were in the bay.
But as the afternoon wore on, producing only a false sighting of two gray whales, officials grew increasingly confident that the humpbacks, which were injured by a boat during their two-week sojourn inland, were on the move and made plans to stop searching for them.
Marine scientists said Wednesday that although they will never know why the pair swam 90 miles inland, the operation to rescue the humpbacks yielded valuable information about the endangered species. It was the first time the same humpbacks were studied in the wild for so long, they said.
The information scientists gathered includes sound recordings, logs of their behavior and tissue samples, which will be analyzed to determine if they come from a pod of whales that travel between Mexico and California.
“All those things are very hard to get. So what we are doing is filling up the knowledge bank on humpback whales in the wild,” said Jim Oswald, a spokesman for the nonprofit private Marine Mammal Center, adding that the experience could prove helpful in approaching other stranded whales.