Two Southern Resident orcas who were last seen in poor health are missing from their family groups.

Researchers with the Center for Whale Research saw all members of the J17s and K13s in Haro Strait on Friday and Saturday except for J17 and K25, who are believed to be in deteriorating condition. Although the researchers said the encounters weren’t enough to determine anything “definitive,” it was concerning that those two whales were missing for two straight days.

“We will continue to look for J17 and K25 in upcoming encounters but the chances of finding them are starting to look a little grim,” researchers wrote in a Center for Whale Research blog post.

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J17, a 42-year-old female orca, is believed to have peanut head, which is a depression at the base of the neck due to fat loss and a sign of malnutrition in whales. Scientists with the National Oceanic and Atmospheric Administration took drone photos of J17 and her daughter J53 in May that showed the pair had deteriorated.

If J17 is presumed dead, researchers have cause to worry for her son J44, because there’s a three times greater chance a male orca will die after his mother dies.

K25, a 28-year-old male orca, was last seen in January. His declining health was first documented last fall when photos showed that he appeared to have lost weight between September 2017 and September 2018.

The orcas’ absence comes on the heels of a sliver of hope for whale researchers. On Friday scientists confirmed the birth of J56, a female calf who is believed to have been born in late May to 24-year-old J31. It’s the second Southern Resident calf who was born in the last six months; L124 or Lucky was believed to have been born in December.

WATCH: Female orca calf found with J pod

With the orca births, the Southern Resident population sits at 76 whales. A variety of factors are blamed for their struggle to flourish, including boat noise, pollution, and dwindling Chinook salmon returns, which is their preferred food.

The plight of the orcas captured the world’s attention last summer when J35 carried her dead calf for 17 days. Shortly after 3 ½-year-old orca J50, who also had peanut head, disappeared from her pod.

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