PR 26 07

FOR IMMEDIATE RELEASE

THURSDAY, June 14, 2007

CONTACT: Brian Gorman, NOAA, (206) 526-6613

Nola Leyde, Corps, (206) 764-6896

Scott Simms, BPA, (503) 230-3520

• Adult spring chinook returns low, as predicted
• Juvenile survival in Columbia Basin shows marked improvement
• Return of “jacks” close to record

PORTLAND, Ore. – Government and university scientists, whose pre season forecasts of adult chinook salmon returns ranged from 78,500 to 83,000 fish, were right on the money according to the latest counts at Bonneville Dam in the Columbia River. With the close of the spring chinook season coming officially on June 15, the count is expected to be close to 80,800 adults, below the 10-year average of about 175,000 and less than last year’s returns of 126,158 Chinook, but well above the record low of 12,780 adults in1995.

The “ocean index predictor” from the National Oceanic and Atmospheric Administration (NOAA) showed that almost all ecosystem indices measured in 2005 also pointed to low adult returns of spring chinook in 2007.

“We’ve seen wide fluctuations in adult returns over the past 30 years,” said John G. Williams, a research fishery biologist with the NOAA Fisheries Service. “That’s to be expected when the changeable ocean, where salmon spend most of their lives, has such a powerful influence on adult survival.” 

But Williams said data on survival of juveniles through the Snake and Columbia river dams in recent years were very encouraging. “Juvenile survival past the dams – a crucial aspect of salmon recovery and one where humans actually have some measure of control – has steadily improved,” he said. “It’s now about two times higher than the average in the 1970s.”

According to the NOAA Fisheries Service, juvenile survival of spring chinook through the eight hydropower dams in the Basin in 2006 was the highest ever measured in 30 years.

By increasing juvenile survival to the ocean, government scientists say, adult returns are likely, on average, to improve over the long term.

Since the 1970s, major changes have been made to the dams and how they are operated.  Screening turbine intakes, reducing harmful atmospheric gas in the waters just below the dams and improving water flows and spill during the spring migration have all led to better conditions for young fish.  More recently, the installation of fish slides at Lower Granite, Ice Harbor and McNary dams and a specially designed bypass channel to guide juveniles past Bonneville Dam, have increased survival of young salmon on their way to the ocean, according to scientists.

Scientists also say prospects for adult returns in 2008 and beyond appear bright.  The number of jacks – adult chinook that return to the river early, just a year after they migrated to the ocean – is expected to be just over 20,000, the second highest number since records of jacks started in 1977 and more than double the 10-year average.  Jack returns are generally considered a good predictor of overall adult returns the following year.