Three killer whales discovered in fresh water far up Southwest Alaska's Nushagak River have state and federal biologists considering options to intervene and move them back to the ocean.
The two adult whales and one juvenile were spotted three weeks ago on the Nushagak and have been lingering about 30 miles up the river from Dillingham, near a fork south of the village of Ekwok, according to the National Oceanic and Atmospheric Administration. Local residents say the whales are about an hour's boat ride upriver from where the river's freshwater mixes with Nushgak Bay's saltwater.
While residents have seen killer whales at the river's mouth before, it's the first documented case of killer whales traveling this far up the Nushagak, NOAA says. It's also the first report in Alaska of killer whales staying for prolonged periods of time in a freshwater river, NOAA Alaska fisheries spokeswoman Julie Speegle said.
It's unclear why the whales swam so far upriver. And they aren't showing any signs of leaving, Speegle said. Federal and state biologists are watching the whales' condition to see if they should step in to help, she said.
"They have developed a sort of filmy covering that is typical for marine mammals to develop in fresh water," Speegle said. "It's an indication of freshwater stress."
Another cause for concern: cooling temperatures, said Barbara Mahoney, a biologist with NOAA's National Marine Fisheries Service.
As winter approaches, melting of snow and glaciers slows in the mountains that feed the Nushagak, causing the river to drop, Mahoney said. Mahoney had heard reports of the river dropping, and a shallower river would mean more difficult passage for the whales, she said. The river usually freezes over by late October or early November, she said.
"We are coming up against some natural, weather-related time lines," Mahoney said.
Alaska killer whale expert Craig Matkin said the whales of this type -- so-called transient killer whales, which feed on other marine mammals as opposed to fish -- are likely suffering from starvation. Matkin said he's not sure what they could be feeding on that far up the river.
"From what I understand, there's no suitable prey for them -- seals, sea lions, anything," Matkin said. "Maybe beavers, but I don't think that's going to make it for them for too long."
"I think we're all wishing they would just turn around and go back out, and we're all thinking, well, maybe there was a reason, but I can't imagine a reason for them to stay up there," Matkin said. "There's just not enough prey. There's just no way that that would be the case.
The best-case scenario would be for the whales to swim down the river to the ocean on their own, Speegle said. If they appear to be in serious danger, biologists might decide to herd them, she said.
Stronger methods -- such as lifting the whales out by helicopter or boat -- are unlikely, said Speegle and Mahoney.
"With marine mammals, they're just so large that being out of the water creates problems," Mahoney said. Those problems include keeping a whale's organs working under its immense weight, she said.
The best option is using noise, Mahoney said.
In 1994, Southeast Alaska residents in boats worked with biologists to herd a pod of starving killer whales out of Barnes Lake and into open ocean using "bang pipes," said Seattle biologist Marilyn Dahlheim. The metal tubes are sealed off at one end, dipped in water, and pounded on the side with a hammer. The noise drives whales away and, hopefully, toward safety, she said.
"Those bang pipes were really successful," Dahlheim said.
As biologists work out the many variables involved in herding the whales, the Fisheries Service is warning people to stay away from them, Speegle said.
"Orcas are predatory, and they're large, so for people's own safety and the well-being of the whales, we're asking that people not approach them and stay at least 100 yards distance," Speegle said.
Still, whale sightings on the river are causing a stir, said Jon Sharp, a teacher in New Stuyahok, farther up the Nushagak from Ekwok. After hearing about the whales from students, on VHF radio and from local pilots, Sharp took a skiff down to see them on Tuesday, he said.
"We got off on a bank and walked down. You could see them finning. They weren't very active at all," Sharp said. The whales swam about 300 yards upriver, then returned, he said. "They just kept coming up and down slowly. There wasn't much to see, and the only reason we stayed was that it was so unique."
Sharp said it was the first time -- aside from a visit to SeaWorld -- that he'd seen killer whales.
"You move up to a river community, you don't expect to see any marine mammals. The closest thing is like a seagull."
Reach Casey Grove at firstname.lastname@example.org or 257-4589.