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Chinook Adult Passage at Bonneville Dam![]() ? 2003 Fish Passage Center |
Through October 31, with only a few weeks of counting left, 918,071 chinook salmon had been counted crossing Bonneville Dam, according to information complied by the Fish Passage Center. That is more than twice the average annual count for the most recent 10 years at Bonneville, 397,878 fish. Steelhead counted at Bonneville in 2003 totaled 361,518, compared to the 10-year average of 278,729. Coho totaled 125,275 in 2003, compared to the 10-year average of 59,304. Only the sockeye count at Bonneville, 39,291, is lower than the 10-year average (46,748). These counts are of adult fish only and do not include jacks, which also were well above the 10-year averages in 2003. Jacks are immature fish that return after one year in the ocean; their numbers are considered a reliable indicator of the size of the next year's runs.
The Council report shows that the gains of recent years are even more striking when compared to returns during the mid-1990s, when the runs declined. Consider spring chinook, for example. The annual average count at Bonneville for the years 2001-2003 is 297,346 fish, compared to an annual average of 29,770 from 1994 through 1996, a 10-fold increase. At Lower Granite Dam, the last of eight dams on the lower Columbia and Snake Rivers that spring chinook cross on their way to spawn in Idaho, Washington or Oregon, the annual average for the years 2001 through 2003 is 110,370 fish, compared to an annual average of just 3,478 for the years 1994-1996, almost 32 times as many fish.
While no single cause is apparent for the big upswing in fish returns, a number of factors likely are contributing. For the last several years feeding conditions have been favorable in those areas of the Pacific Ocean where Columbia basin salmon and steelhead are known to spend their adult lives. Increases in the number of fish released from hatcheries probably had a part, too, as did reduced harvests in the ocean and improvements in freshwater spawning and rearing habitat achieved largely through the Council's fish and wildlife program.
The Council is an agency of the states of Idaho, Montana, Oregon and Washington and is directed by the Northwest Power Act of 1980 to prepare a program to protect, mitigate and enhance fish and wildlife of the Columbia River Basin affected by hydropower dams while also assuring the region an adequate, efficient, economical and reliable power supply.
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