The orca who was spotted Thursday off British Columbia is thin and in poor health.
Sheila Thornton, lead killer whale research scientist with Fisheries and Oceans Canada, said they are anxious that the time and energy it spends carrying the body could take away from foraging or feeding.
It's made up of three pods, all of which have been listed as endangered in both the USA and Canada.
J50, the ailing 3 1/2-year-old orca, was seen along with her mother, J16.
Brad Hanson, of the US National Oceanic and Atmospheric Administration (NOAA), added: "It would be very challenging and perhaps not in the best interest of the animal to go in and remove the calf".
When the water calmed, the team was also able to get a sample from her blow hole, which he said they believe will be very valuable to assess.
Fearing that J50's fate will be the same if they don't intervene, scientists are considering multiple strategies created to save the starving whale, including feeding her live salmon dosed with medication at sea.
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Tahlequah, referred to by scientists as J35, was spotted Wednesday by Canadian scientists pushing the body of her calf off the coast of the Olympic Peninsula. "Is that not only is she not improving, it looks like she's deteriorating over the period of time when we would expect to see the condition improve". They are waiting for her to show up again in Washington state waters so they can zip out on a boat to do a health assessment, said Teri Rowles, marine mammal health and stranding coordinator for NOAA Fisheries.
In the United States, biologists have prepared veterinary supplies, and dart and injection guns with antibiotics to rapidly respond when they see the killer whale.
"Removing the calf would be a very, very hard decision, and obviously we would have to take many factors into consideration, so that's now not on the table", she said.
If you'd like to be a part of the solution to saving these attractive whales, one easy step you can take is to reduce or completely do away with your personal consumption of seafood. Scientists are anxious about her and will watch her but don't have plans to help her or remove the calf. We know they're capable of emotions like grief because the parts of their brains that do social and emotional work are big and elaborate, and they even contain specialized empathy cells called von Economo neurons, which help highly social animals like primates, elephants and whales achieve the extreme levels of cooperation that's required of them.
The group will prioritize short-term and long-term actions, many of which are certain to focus on recovering the prized salmon that the fish-eating whales like to eat.
The last time scientists rescued a killer whale in the region was in 2002 when a northern resident killer whale known as Springer was found swimming alone in Puget Sound. Tahlequah is not carrying that calf's body all by herself - members of her family have been helping her with her vigil.
"What we are going to concentrate on in the next few days is her ability to eat", said Haulena.