Every one who cares about salmon and dams on the Snake and Columbia rivers is wondering why so many sockeye salmon have returned to the rivers this year.

As of July 13, 211,794 sockeye have returned to Bonneville Dam, the first dam they encounter when returning from the Pacific Ocean. That number is four times the 10 year average.

For us Idahoans the critical number is the even more astounding return of Snake River sockeye salmon to Lower Granite Dam on the Snake River near Lewiston. So far 737 sockeye made the trip compared to 36 in 2007 and a 10 year average of 35.

Snake River sockeye are the most endangered salmon in the Columbia River watershed so these returns are great news. Many scientists and even supporters have suggested in the last few years that these fish, propped up with a huge and expensive captive breeding program, were functionally extinct.

The Fish Passage Center, the little agency that analyzes the migration of salmon through the dams of the Snake and Columbia rivers, has some answers as to why the sockeye are doing so well. As has repeatedly been the case for this scientifically driven agency, its findings don’t fit the politics of the region.

High water and artificial spills over the eight dams, which is water diverted from the hydroelectric turbines to the spillways, is one of the major factors the Fish Page Center scientists say. The other is that fewer sockeye were placed in barges used to carry salmon through the dams, a practice that allowed more hydroelectric production.

“Among the years analyzed, migration years 2006 and 2007 resulted in some of the lowest estimates of proportion of juvenile sockeye transported,” the Fish Passage Center memo said. “In fact, with exception to 2000, the proportion transported in these two years was substantially lower than the other years analyzed.”

If the Fish Passage Center is right the two things that helped sockeye the most are practices that are costly to Pacific Northwest electricity customers because they lead to reduced power production. It also challenges the immediate assumption of federal biologists that the improved returns for sockeye as well as other salmon in the Columbia River this year is due to good ocean conditions.

It also supports the idea that breaching the four lower Snake dams in Washington would dramatically benefit Snake River salmon because their removal would shorten the travel time for salmon even better than high flows and spills.

It’s still possible that the places in the ocean the Columbia fish go have better conditions than the fish from southern rivers, where the salmon runs are a disaster. It’s even possible that the Columbia fish’s haunts in the Pacific fared better than the places where salmon from British Columbia go, which are also struggling this year.

These are the kinds of debates you can expect to hear for the next year. Also expect Judge James Redden, who has based some of his decisions on the results of the Fish Passage Center research, to be reading the memos closely.