Alaskans again this summer are wondering: Where are the king salmon?

Some of Alaska's largest and best rivers are closed to king fishing because state and federal fisheries managers have determined that the largest of the salmon species, also called Chinook, aren't showing up in enough numbers to ensure sustainable future runs.

In western Alaska, people living in dozens of villages along the Yukon and Kuskokwim rivers are turning to less desirable salmon species — fish with lower oil and fat content — to fill their freezers for winter in what one official described as a summer of "food insecurity."

"It is pretty scary," said Timothy Andrew, director of natural resources with the Association of Village Council Presidents in Bethel. "Chinook salmon is probably the biggest species that people depend on for drying, salting and putting away in the freezer to feed the family throughout the winter."

Fishery managers predict that this year's Yukon River king salmon run will be worse than last year, and that was the worst showing for Chinook in 30 years.

Commercial fishermen on the Yukon and Kuskokwim are turning to less desirable but more plentiful species of salmon that sell for under $1 a pound. King salmon sells for more than $5 a pound. With gas costing $6.70 a gallon in Bethel, many fishing boats are sitting idle, he said.

People living in the region's 56 villages are devastated, Andrew said.

"It is an incredibly stressful time," he said.

In mid-July, the Kenai River — considered by many to be Alaska's premier river for salmon fishing — is normally crowded and chaotic with fishing guides steering their boats to give their clients the best opportunity to catch a trophy king.

But a ban on king fishing on the Kenai and Kasilof rivers went into effect Thursday.

Robert Begich, the Alaska Department of Fish and Game's area management biologist, said the Kenai king run looks to be the lowest on record going back to the 1980s.

While the continued downward trend in kings isn't clear, Begich suspects a combination of factors, with researchers looking more closely at changes in the ocean environment. King salmon usually spend several years in the ocean before returning to rivers to spawn.

Ray Beamesderfer, a consultant with Cramer Fish Sciences in Gresham, Ore., also suspects changes in the marine environment. He thought he and his family would be fishing for king salmon on the Kenai River on Thursday. Instead, they were casting for rainbow trout or smaller sockeye salmon.

Beamesderfer said in the late 1970s, there was a change in ocean currents that favored Alaska salmon but contributed to poor salmon runs in the Pacific Northwest.

That situation appears to be reversing, with a change in ocean currents, he said.

"We have seen some better runs in recent years," Beamesderfer said.

But he said the persistent downturn in king salmon can't be fully explained by a change in ocean currents, especially when other salmon species in Alaska are thriving.

"It doesn't seem to be that simple," Beamesderfer said.

Jeff Regnert, director of the commercial fisheries division for the Alaska Department of Fish and Game, also said something different in the marine environment likely holds the answer to the downturn in kings.

"That is probably where we will see the change," he said.