As of Wednesday, only 2,009 kings had been counted through a weir on the iron-colored stream west of Willow. Three or four times as many should have come back by now.

No one knows the reason for the run failure. Everything from flooding possibly washing eggs out of the river to growing catches of immature king salmon in Bering Sea pollock trawls to colder than normal ocean temperatures in the Gulf of Alaska have been blamed.

It is not the only Southcentral salmon run in trouble either. On Tuesday, Fish and Game banned keeping king salmon on Ayakulik River and red salmon on the Karluk River on Kodiak Island while closing the popular Buskin River close to town. All three are showing miserable returns so far.

On the other hand, the early king salmon run on the Kenai River is running about normal.

Biologists note a lot of variables affect salmon survival, and a change in any of them can bring a run crashing down.

What is staggering about the Deshka this year is the size of the crash. Based on the number of spawners through the weir as of Wednesday, the total return is projected at only 4,112 fish.

That is only about 30 percent of the minimum goal of 13,000 fish biologists want on the spawning beds come late summer to ensure future runs.

To try help ensure the maximum number of fish make it back, Fish and Game terminated the last fishing period for a gillnet fishery at the mouth of the Susitna River along with closing the season for angling.

The latter closure begins at 11 p.m. Friday.

The shutdown marks the first time the river has been closed to king fishing since 1996.

"It's a tough deal,'' said area biologist Dave Rutz. "It's a tough call to do this on a Friday."

But he added, there was little choice. Only about 150 kings passed through the weir Wednesday. Biologists had hoped to see many hundreds more. The small number indicated the run had hit and passed the first peak in a traditionally undulating return. Another peak is expected later in the month or in early July, but it is historically smaller than the June peak.

No one expects it to bring enough fish to make the spawning goal or allow a reopening of the fishery, although anglers always hold out hope.

Reporter Stephanie Komarnitsky contributed to this story.