A hungry orca that biologists hoped to save was declared dead only 24 hours after the plans were announced.
Efforts to find the young sick creature, which comes from an endangered population of orcas in the Pacific Northwest, have appeared empty-handed.
Known as J50, the desperately ill animal had not been seen since last Friday.
The gloomy news leaves only 74 whales remaining in a group that did not reproduce successfully in the last three years.
Killer whales have struggled with pollution, noise from boats and, what is more serious, the scarcity of their preferred prey, chinook salmon, due to prey, habitat loss and overfishing.
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A hungry orca that biologists hoped to save was declared dead only 24 hours after the plans were announced. In the photo is the young orca with her mother
"We are watching a population marching towards extinction," said Ken Balcomb of the Whale Research Center.
"Unless we do something about salmon recovery, we will not have these whales in the future."
The whales are so poorly trained that the experts prepared desperate efforts to save the emaciated four-year-old boy.
A leading veterinarian shot him a dart full of antibiotics, without success, and the scientists even thought about capturing it so that they could treat it for parasitic worms.
While the teams struggled to find her on Thursday, she did not reappear with her pod, despite the favorable viewing conditions.
Balcomb, who tracks the whales for the US government, declared her dead late yesterday afternoon, although authorities said they would continue searching.
Michael Milstein, spokesman for NOAA Fisheries, said the agency places great importance on Balcomb's assessment of whales, given their long experience of supervising them
But, he said, because the governments of the United States and Canada have so many resources dedicated to finding it, they planned to continue the search today.
"We want to make the most of it to make sure that if J50 is there, we have not missed it," Milstein said. "We have not lost hope."
Efforts to find the young sick creature, which comes from an endangered population of killer whales in the Pacific Northwest, have appeared empty-handed (stock image)
The crews of a helicopter of the US Coast Guard UU., Ten vessels, whale watching crews and other resources on both sides of the border participated in the search.
Authorities also alerted a network of people who respond when marine mammals bathe on land.
The whale experts feared that the orca would die earlier this month, when J50 was left behind with respect to her family and disappeared, but then she appeared and was seen with her family.
The distinctive black and white killer whales, known as Southern Orcas, have had problems since they were included in the list of endangered species in the US. UU And Canada more than a decade ago.
Orca numbers are now at their lowest point in more than three decades.
Last month it was discovered that the killer whale, in danger of extinction, that had clung to its dead calf for more than two weeks and was swimming for 1,000 miles, had finally released its baby.
Another whale in the same herd, known as J35, sparked international sympathy this summer when he kept the body of his dead calf afloat in the water for more than two weeks.
The message, Cente for Whale Research said in a publication on the website, is that extinction is looming, while humans convene working groups and conferences that result in nothing, or worse than nothing, distracting attention and resources from the solution of the underlying ecological problems. .
The scientist began to worry about J50 in July.
The teams threw live salmon from a boat like J50 and its pod swam behind, a test to see if the fish could be used as a means to administer medication.
The images of drones taken earlier this month showed that J50 was much thinner than last year.
His mother, J16, has also decreased his condition in the last month.
Researchers previously monitored the activity of a grieving orc mother, while towing the body of her dead calf through Puget Sound, British Columbia, after she passed away on July 24.
WHY DO SCIENTISTS THINK THAT WHALES AND DOLPHINS CRY?
Whales and dolphins have been seen & # 39; bearing & # 39; or taking care of their dead young several times.
These creatures may be in mourning or have not accepted or acknowledged that the offspring or partner have died.
Scientists still do not know if aquatic mammals really recognize death and are looking to do more research on this subject.
In 2016, scientists found evidence that whales and dolphins perform "vigils" for their dead.
They analyzed several cases in which mammals clung to the bodies of dead compatriots and watched over a dead companion.
At that time, they said that the most likely explanation was mourning.
The study compiled observations of 14 events.
They discovered that mothers used to take their dead youngsters over the water, often flanked by friends.
In many cases, the dead pups broke down, indicating that they had been kept for a long time.