the film forum library tutorial contact |
Return of the Sockeye and
by Don Brunell |
In 1992, a single male sockeye salmon managed to swim 900 miles from the mouth of the Columbia River to Redfish Lake in Idaho's Sawtooth Mountains, the end of his migratory journey. Biologists dubbed him "Lonesome Larry."
This year, the Northwest Power and Conservation Council happily reported record-setting runs for sockeye in the Columbia and Snake rivers and their tributaries. Nearly 387,000 had climbed the fish ladders at Bonneville Dam and, by mid-August, 2,100 passed through the fish counters at Lower Granite Dam, the last counting station on the Snake just west of Lewiston, Idaho.
The resurgence of the Snake River sockeye, an endangered species, is good news for fisheries biologists who have been working for 20 years to rebuild the sockeye populations with a combination of hatchery production and habitat improvements.
But the real measure of the "Sockeye Surprise," as the council coined it, is the returns to Redfish Lake. The Redfish Lake sockeye were listed as an endangered species in 1991 and were thought to be destined for extinction. But this year, they are returning by the thousands.
The sockeye first faced extinction when Sunbeam Dam was built on the Salmon River in 1910. When the dam was removed in 1931, the sockeye rebounded to 1,500 returning spawners by 1955.
The population took another dive after the four lower Snake River dams were completed, but with a lot of attention, money and applied science, the Idaho Department of Fish and Game reported that 1,300 sockeye returned to Redfish this year.
The good news goes beyond sockeye. The Oct. 22 issue of the Columbia Basin Fish and Wildlife News Bulletin reports a huge return to the Snake River Basin of 2010 fall Chinook - the prized king salmon - more than double the modern-day record. As of Oct. 22, 41,526 fall Chinook had been counted climbing over Lower Granite Dam's fish ladders, more than twice the previous high recorded for the entire 2008 season, and the Chinook migration continues into this month.
With all of the good news, what could possibly go wrong?
Biologists are reporting that federally protected California sea lions, which have a ferocious appetite for salmon and steelhead, continue to follow the runs up to Bonneville Dam and are swarming at the base of the dam. Their consumption is increasing, and unlike fishermen, the marine mammals don't distinguish between hatchery fish and wild stocks.
Secondly, while dam operators, foresters and agriculture managers have greatly increased the number of young salmon that head downstream toward the ocean, those fish are being hijacked just before they make it to the Pacific.
The young salmon must swim past East Sand Island in the lower Columbia River. The island, which was created from the dredging of the river after the Mount St. Helens eruption in 1980, has become home to the world's largest population of Caspian terns - voracious predators that last year ate an estimated 6.4 million young salmon. The island is also home to the largest colony of double-crested cormorants in western North America. Last year, cormorants killed an estimated 11 million juvenile salmon.
The point is this: Those who simply call for the removal of the four lower Snake River Dams should acknowledge the progress irrigators, foresters and dam operators are making to restore Columbia and Snake River salmon and steelhead runs - progress that is being made despite heavy losses from sea lions, terns and cormorants.
It is an example of how applied science can work. Lonesome Larry would be proud.
Excerpt from Suvival of Snake River Salmon & Steelhead Data compiled July 2004 by bluefish.SUMMARY
In the case of Snake River spring chinook, an adult female lays about 5000 eggs.
5000 eggs per adult spring chinook pair.
400 smolt migrate, assuming 8% survival.
200 - 280 smolt survive to first reservoir, assuming 50% to 70% survival.
81 - 113 survive the Hydrosystem Corridor as juveniles, assuming 40.3% survival.
57 - 80 survive bird and seal, sea lions predation in the estuary, assuming 71.2% survival.
18 - 51 survive delayed effects of the Hydrosystem, assuming 32% to 63% survival.
0.36 - 3.0 survive years in the ocean to begin upstream migration, assuming 2% to 6% survival.
0.32 - 2.7 survive seal and seal lion predation and harvest, assuming 87.5% to 88% survival.
0.23 - 1.9 survive the Hydrosystem Corridor as adults, assuming 72.2% survival.
0.18 - 1.7 adult progeny survive to spawning grounds, assuming 80 to 90% survival.
learn more on topics covered in the film
see the video
read the script
learn the songs
discussion forum