The walrus, nicknamed Freya, attracted crowds while basking in the Oslo fjord this summer but was euthanised on Sunday.
Officials said it was the only option after determining they could not “guarantee the wellbeing of the animal”.
The head of the Norwegian Directorate of Fisheries, Frank Bakke-Jensen, received death threats from Norway and all over the world on Monday after the decision to put down the walrus was reported, broadcaster NRK reported.
Bakke-Jensen’s wife, Hilde Sjurelv, was also the target of threats according to the report.
“It’s completely fine not to agree, but making death threats is going too far. That’s going too far,” Sjurelv told NRK.
Sjurelv has received abuse based on both who she is and her appearance but cited the death threats as the worst of the messages. Several of the messages have been seen by NRK, the broadcaster writes.
“I was shaken and scared when unpleasant messages and comments began pouring in on my phone,” Sjurelv said.
“This is about an issue I have nothing to do with, apart from being married to Frank,” she said.
“I think many people from different countries can express their view but they should limit it to disagreeing and not make direct death threats,” she said.
She has now made her Facebook profile private, she said.
Bakke-Jensen said he would report the threats to police.
“I have no problem receiving complaints or objections about my job to me personally. But I think it’s way over the line to contact my family. But that has unfortunately become part of everyday life,” he told NRK.
“My own safety is taken care of, so I’m not too concerned about that. This is an issue that has been very emotive and that can set off a lot of irrational forces, so we get examples like this,” he said.
The director of the Fisheries agency said he did not think he or his wife would be in need of added security.
“I will do as I have done before, save and send on to the police, and their experts will assess it,” he said.