The whale drew big, curious crowds since swimming into the river with its calf in late June, taking refuge in fresh water for an unknown reason while migrating north from the birthing grounds off Baja California. Scientists said it may have been escaping from killer whales.
Efforts to drive it back to sea with calls of killer whales played upriver and other measures could not persuade the whale to leave, but the calf swam out to sea on July 23, about the right time for it to wean and go off on its own.
But the mother remained, sometimes feeding on invasive species of clams and snails in the mud of the river bottom, blowing great geysers of air and water out of her blowhole, and spending much of its time within sight of people who lined a U.S. Highway 101 bridge over the river.
Its behavior enthralled people who stood in the river playing violins, paddled out to the whale in canoes playing flutes, and jumped out of kayaks to swim with the huge animal.
"It's very sad," said Thomas O'Rourke, chairman of the Yurok Tribe, whose reservation lines the banks of the river south of Crescent City, Calif. "It started to become a part of the community."
The while died about 4 a.m. as it was observed by a number of scientists. A cause of death will be determined in a necropsy after researchers move the marine mammal.
"Based on the photos and everything, her fat layer looks good, so we don't think she starved to death. There's something else going on," said Sarah Wilkin of the National Oceanic and Atmospheric Administration. She was part of the team studying the whale and urging it back to the Pacific.
Ashala Tylor, a freelance photographer, has been making pictures of the whale for weeks and said she saw it alive Monday night.
"I stayed until about 2 a.m. this morning and she was swimming around the bridge," Tylor said. "When I came back this morning she was on her side as dead as can be. I was shocked when I saw her."
The last time wayward whales made headlines in California was in 2007, when a mother humpback and her calf journeyed 90 miles up the Sacramento River. The two whales were followed by crowds for more than two weeks before swimming back out to the Pacific Ocean at night.
O'Rourke visited the dead whale and said a prayer for its new journey. He believes the whale might have been showing its calf a place it had known in its youth.
"This is the farthest up river I have ever seen a whale," he said. "They come into the mouth regularly, the bottom end of the estuary. I believe there is a message there, and we are still yet to understand."
Jason Dearen reported from San Francisco. Jeff Barnard reported from Grants Pass, Ore.
Jeff Barnard can be contacted at http://twitter.com/JeffBarnardAP
Jason Dearen can be reached at --http://twitter.com/JHDearen