vanishing salmon

Wow. Interesting story in the NY Times about king salmon in the Sacramento River. Apparently the run crashed and scientists are trying to figure out why. One of the ideas is a climate-related, out of sync pattern of ocean currents.

After studying changes in the once-predictable pattern of the Northern Pacific climate, Mr. Petersen found that in 2005 the currents that rise from the deeper ocean, bringing with them nutrients like phytoplankton and krill, were out of sync. “Upwelling usually starts in April and goes until September,” he said. “In 2005, it didn’t start until July.”

Mr. Petersen’s hypothesis about the salmon is that “the fish that went to sea in 2005 died a few weeks after getting to the ocean” because there was nothing to eat. A couple of years earlier, when the oceans were in a cold-weather cycle, the opposite happened — the upwelling was very rich. The smolts of that year were later part of the largest run of fall Chinook ever recorded.

The story doesn't specify what's driving the climate variance, but changes in sea ice melt, upwelling, and plankton blooms are predicted with man-made warming. Also interesting is that they're talking about 2005, which means the fish that are missing are the three year olds. Up here, kings are more often 4 or 5, I think, and used to be older more often, when they return upriver to spawn. If that's true down there, than a bad smolt year in 2005 will mean bad runs for years to come. Click here for the whole story.