Teams are searching for the sickly orca known as J50, but a scientist who tracks the whale population said today that she is likely dead.

Experts have been preparing last-ditch efforts to save the emaciated whale that included the possibility of capturing and treating her.

A spokesman for NOAA Fisheries said boats and planes in the U.S. and Canada are looking, but J50 has not been seen in recent days with her family. She went missing earlier this month, but later turned up.

The loss of J50 would bring the number of southern resident killer whales to just 74 animals.