J Pod was seen off the south end of Vancouver Island by Canada's Fisheries and Oceans personnel late Tuesday.
Canadian and US scientists are particularly anxious to save J50, a juvenile female that has the potential to reproduce and assist with the population's recovery. "It's fantastic. We're hoping she's going to be OK". J50 needs the nutrition not only for the calories, but to rehydrate her.
The first step before administering any antibiotics will be to assess J50's condition, once she is located again in appropriate conditions.
On Tuesday, the whales were spotted in rough waters off Port Renfrew. J50 was with her mother, J16, and the rest of the pod.
"As you can tell we've had a lot of challenges in seeing them daily", Milstein said. Then the whales disappeared back into the fog. Biologists and veterinarians are standing by to do a health assessment, including taking samples of the whale's breath, and collecting her scat from the water.
Veterinarians in the field will decide whether to give the ailing orca antibiotics, which would last between 10 and 14 days, using either a dart injector or a long pole syringe.
Rowles said injections of antibiotics or sedatives have been given to other free-swimming whales or dolphins that were injured or entangled but it hasn't been done for free-swimming whales in this area.
If things go well, she said, the team could move ahead with feeding the orca live salmon from a boat.
The weather and the location of the orcas are complicating factors that could prevent intervention, said Paul Cottrell, a marine mammals co-ordinator with DFO.
Rowles said such imagery has shed more light on the whales' overall body condition and growth over time. Researchers cite a shortage of chinook salmon as one of the main reasons for the orcas' decline.
"We would be ideally approaching her when she is separated from her pod members, which is not unusual for her", said NOAA Regional Stranding coordinator Kristin Wilkinson.
"It's been a number of days since Friday, so it was great to see J50", Cottrell said.
The southern residents are critically endangered, with just 75 animals in the J, K, and L pods that frequent the region's waters following the chinook on which they feed.
"Hopefully, they are doing well and foraging and doing what they need to do".
Delivering potentially life-saving treatment for an emaciated killer whale could depend on whether it is found in Canadian or American waters.