"It's a great relief that she's still alive", said Paul Cottrell, marine mammals co-ordinator with the Department of Fisheries and Oceans.
Michael Milstein with NOAA Fisheries said J50 was seen with her mother, J16, which is a good sign.
Cottrell couldn't say when the Canadian approvals would be in place, but said the process involves reviewing the proposal against the Species at Risk Act, consulting experts and considering regulations against feeding killer whales that were put in place to prevent habituation to humans.
J50 is one of only 75 remaining southern resident killer whales that are found in coastal waters from B.C.to California.
It is charged with examining the threats and conditions that have depleted the southern-resident killer whales, and recommending a recovery program. They became anxious when her pod, last seen Friday, wasn't spotted for several days.
Her pod recently drew an global spotlight when another whale, J35, was spotted pushing the body of her dead calf through the water for more than a week.
An emaciated and endangered killer whale believed to be near death has been spotted near the coast of Vancouver Island for the second straight day.More news: Virginia governor declares emergency ahead of Charlottesville anniversary
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"It is very possible that she has succumbed at this point and that we may never see her again", said NOAA Fisheries veterinarian Teri Rowles.
Government biologists are considering giving her antibiotics through either food or injection.
Thornton cautioned, however, that Canadian officials have to follow federal law, perform a thorough risk assessment and minimize the impact of any intervention on J50 and her podmates.
Another possibility is administering a long-acting antibiotic with a pole injection system if they're able to get close enough to the orca. As a young female, experts say, she has reproductive potential and could play a vital role in the southern residents' recovery. They may drop medicated fish next, if that goes smoothly.
A team of global scientists hope to get close enough in order to inject her with antibiotics. King County has lent its new research boat, the "SoundGuardian", to the cause, according to county Executive Dow Constantine's office.
American and Canadian scientists are considering a Hail Mary effort to save an endangered four-year-old killer whale, known as J50, which appears emaciated, lethargic and has lost about 20 per cent of its body weight.
Biologists have also considered feeding the orca salmon enhanced with vitamins or medication to try and boost her health, which would have to be undertaken on a daily basis.