Earlier this month, as the Oslo Fjord was basking in the sunshine and full of swimmers, boaters and children enjoying their last week of summer vacation, it had a visitor: a 1,300-pound walrus named Freya.

Last week was different. Not only has school started again and the weather turned, but the walrus, who had been a source of delight and had become something of an international celebrity, is dead.

On Sunday morning, Norwegian authorities killed Freya, saying she posed too big a threat to humans who failed to listen to repeated warnings to stay away from her. Moving her out of the area was “too high risk,” officials added.

Environmentalists and Freya’s fans on social media said the decision to kill her, just three days after the warning that she might have to be put down, was hasty and unnecessary.

But the Norwegian Directorate of Fisheries said in a statement that it was the only option after the public did not heed the warnings.

“I am firm that this was the right call,” the director general of the directorate, Frank Bakke-Jensen, said in the statement. “We have great regard for animal welfare, but human life and safety must take precedence.”

The Norwegian Institute of Marine Research had considered moving Freya out of the area, Bakke-Jensen added, but “the extensive complexity of such an operation made us conclude that this was not a viable option.”

Moving a 1,300-pound mammal isn’t easy. Freya would have needed sedation and then to be caught in a net to prevent her from drowning before being moved out of the area.

In Norway, Freya has dominated the news since she arrived in June, with trackers, Facebook groups and almost daily articles chronicling her plight. A Facebook page called “Freya the Walrus — Where is she now?” had been tracking her. Since Sunday, the group, which has more than 1,000 members, has been awash with sad comments and condolences.

The country’s prime minister, Jonas Gahr Store, said he supported the conclusion that Freya should be put down, telling a broadcaster that it was “the right decision.”

Freya made appearances off the coasts of Britain and various other European countries, including the Netherlands and Denmark, for at least two years.

“Now she comes to this posh, overpopulated beach, and she is dead,” said Trine Tandberg, 62, who runs a children’s theater in Oslo. She said that she had been following the news reports about Freya closely.

“She hasn’t done anything to anyone,” Tandberg said. “That’s what’s making so many of us really, really angry about this whole thing.”

The Oslo Fjord, where Freya had been spending her time, is a densely populated area that includes Oslo, Norway’s capital. About 2 million people live in the region, in a country of just over 5 million.

Walruses are social animals and rarely venture somewhere alone, which might be why Freya seemed to like being around people and why she had sought out a busy area.

“I’m surprised by the speed of the decision” to kill her, said Fredrik Myhre, a marine biologist for the World Wide Fund for Nature in Norway. “They should have been more patient.”

Experts in other countries where Freya had visited over the past two years expressed disbelief at her fate.

“Norway very quickly chose for the very last option,” said Annemarie van den Berg, director of SOS Dolfijn, a Dutch marine rescue organization.