Biologists are still looking for the youngest in a trio of killer whales that swam up Southwest Alaska's Nushagak River, a spokeswoman for the National Marine Fisheries Service said Sunday.
Late Saturday, a biologist with the U.S. Fish and Wildlife Service confirmed the two older whales were dead. That afternoon, the juvenile was spotted downriver of Portage Creek, in a saltwater tidal area.
Scientists believe the whales succumbed to the stress of being in freshwater, outside their normal sea habitat. A team of biologists plan to conduct necropsies this week to learn more about what killed them.
They don't know if the juvenile is still in the river of even if it is alive. A biologist plans to fly over the Nushagak today to look for it, probably searching from Dillingham to Ekwok, said Julie Speegle, a Juneau-based spokeswoman for the National Marine Fisheries Service.
One of the dead whales had washed ashore, but the other was found floating in the river. A local resident took a boat downriver on Sunday, towed the carcass to shore and tied it off.
Local residents said the killer whales had been in the river about three weeks. The trio was spotted last week about 30 miles upriver.
While killer whales are common in the Nushagak's tidal waters in the fall, this year marks the first time the whales traveled so far upriver, and the first time they stayed for so long in freshwater, according to the fisheries service.
Reach Lisa Demer at firstname.lastname@example.org or 257-4390.