Ken Balcomb, head of the Center for Whale Research on San Juan Island in Washington state said the ailing orca who was being treated by scientist since early August was last seen Friday afternoon off the west side of the islands and hasn't been seen since.
The Department of Fisheries and Oceans in Canada and the National Oceanic and Atmospheric Administration in the USA launched a massive cross-border search effort Thursday.
The National Oceanic and Atmospheric Administration in the USA said teams on the water and pilots are looking for J50, who has not been seen in several days. The last known sighting of the 3-year-old orca was on September 7, researchers said.
David Ellifrit/Center for Whale Research via AP J35, also known as Tahlequah, pushed her dead calf around the Pacific Northwest for more than two weeks in what was widely seen as a mourning ritual. J50 has been in poor condition for months and there were concerns over the Labour Day long weekend when she was not seen with the rest of her pod in the waters between Victoria and Seattle. Authorities also alerted a network of people who respond when marine mammals wash ashore.More news: New iPhone Rumors - Here's What We Know So Far
The hotline for stranding reports is 866-767-6114. "We have seen all the other members of her family during these outings", CWR said in a statement. The pods have not had a successful birth in three years. The whales have been struggling with a dearth of their preferred prey, salmon, as well as pollution and boat noise.
The high-profile cases have focused global attention on the plight of southern resident killer whales, whose numbers have dwindled to 75 and now - if J50 has died - to 74 in three pods.
Officials had hoped that J50, born in December 2014, might eventually reproduce and assist with the species' recovery. But, he said the USA and Canadian governments plan to continue searching Friday on the chance she's still alive.
In recent days, they talked about capturing the juvenile whale in the event she becomes stranded or separated from her pod.More news: Jurgen Klopp fires back at Gary Neville
Researchers have been monitoring J50 since noticing her emaciated state. As teams scrambled to find her on Thursday, she failed to appear with her pod once again, despite favourable sighting conditions.
J50's likely death is just another sign of the perilous situation the southern resident killer whale population is facing.
Though J50 has been declared dead, federal officials said the search will continue on Friday, TIME reported.
"(She) definitely captured our hearts, but I don't want to leave you with any false hopes, this is a very sick whale", he said.More news: Marcus Rashford 'to fight for Manchester United place'