Miyoko Sakashita, a lawyer for the Center for Biological Diversity, an environmental group that petitioned the government to expand critical habitat for monk seals, said these types of management actions may be necessary when one seal poses a risk to a population that can't afford to lose any individuals.
"I think this is really just a symptom of the overall problem with the monk seals edging their way toward extinction," Sakashita said.
Michael Hutchins, the executive director of the Wildlife Society, said wildlife managers are increasingly being forced to make difficult ethical decisions to protect species as humans encroach on wildlife habitat.
"Because of our own activities, we've driven many species to the brink of extinction," Hutchins said. "Emergency room ethics are what we are talking about here."
After he's finished in California, KE18 is expected to return to Hawaii and spend his days at Sea Life Park outside Honolulu, one of just four institutions authorized to house Hawaiian monk seals.
Meanwhile, he is eating 10 pounds of fish a day at Waikiki Aquarium and swimming around in his own pool. He's in quarantine, but for KE18, it was almost much worse.