Last week, NOAA confirmed parasitic worms had been found in several fecal samples of the J-Pod whales with whom J50 shares fish, including with her mother. The orcas have struggled with pollution, boat noise and, most severely, a dearth of their preferred prey, chinook salmon, because of dams, habitat loss and overfishing.
Without J50, the population is now down to 74 members - their numbers reached almost 100 in 1995 - and many of its existing female members are nearing the age where they will no longer be able to reproduce, Ken Balcomb, founder and principal investigator of the Center for Whale Research, told The Washington Post in July. But she later turned up and was seen with her family.
The young orca known as J50 remains missing and presumed dead, according to Ken Balcomb, founding director of the Center for Whale Research (CWR). "If we are unable to restore the salmon that these orcas need, more whales will starve to death". As teams scrambled to find her Thursday, she failed to appear with her pod once again, despite favorable sighting conditions. "Not only are the Southern Resident killer whales dying and unable to reproduce sufficiently, but also their scarce presence in the Salish Sea is an indication that adequate food is no longer available for them here, or along the coast".
Another whale in the same pod, known as J35, triggered global sympathy this summer when she kept the body of her dead calf afloat in waters for more than two weeks.
J50 is seen in 2016 with its mother J16.
Officials were searching for the almost four-year-old whale in the water yesterday.
Given the death of Tahlequah's baby, who was also a female capable of reproduction, biologists and government officials began working fervently to devise ways to nurse J50 back to health, or risk losing another potential mother. Efforts to save the sick whale have not been successful.
"She was like this little Energizer bunny that just keeps going and going, and definitely captured our hearts", he said.
"We are increasing water surveillance in hopes of finding her", he said on Twitter.
Joseph Gaydos, a wildlife veterinarian with the SeaDoc Society in Washington state, saw J50 a week ago and described her as the thinnest killer whale he'd ever seen.
The message, the Center for Whale Research said in a website post, is that extinction is looming "while the humans convene task forces and conference calls that result in nothing, or worse than nothing, diverting attention and resources from solving the underlying ecological problems".