Following The Science in Snake River Salmon Declines

***Latest News***

Jean-Michel Cousteau along with more than 118 scientists across the country have sent a letter to the Obama Administration regarding the 2008 federal plan for salmon and steelhead in the Columbia and Snake Rivers.

The scientists’ letter highlights a number of scientific concerns with the Bush plan, including its new jeopardy analysis that would allow just one additional fish returning each year to satisfy ESA requirements, its over-reliance on habitat measures to make up for the harm caused by the federal dams, the roll-backs of in-stream salmon protections like spilling water over the dams, and the “reckless approach to the impacts of climate change on Columbia Basin salmon and steelhead.” Read the letter to the Obama administration.

This comes after a May letter from the Western Division of the American Fisheries Society reasserting the environmental and economic benefits of removing the four lower Snake River dams. The Western Division of the American Fisheries Society represents over 3,000 scientists in the West.  Read the AFS letter.

Fishery scientists have closely monitored Snake River wild salmon population declines since the 1950s. They have studied the plight of the wild salmon in the last several decades using advanced tagging methods and modeling. The role that dams and reservoirs, habitat, hatcheries, harvest, predators and the ocean play in salmon survival is well understood.

Hundreds of federal, state, tribal and independent scientists have concluded that removing the four lower Snake River dams is the best and perhaps only means to protect these fish from extinction and recover healthy populations.

The graph below depicts population trends for wild spring/summer chinook, one of four ESA-listed stocks in the Snake River basin. While the numbers vary for each stock, other stocks have been equally troubled. All wild stocks have seen significant decline; several are on the brink of extinction.

chinook.09.graph  Data source: Idaho Department of Fish & Game; Columbia River Inter-Tribal Fish Commission

The Facts:

•    Most of these fish are as close to extinction today as they were when the first Snake River stocks were listed for protection under the Endangered Species Act (ESA) almost 20 years ago.

•    Since the lower Snake River dams were completed in 1975, wild Snake River spring/summer chinook have never reached their recovery targets, which must be met for eight consecutive years before the species could be considered recovered.

•    Snake River sockeye have rebounded somewhat in the last few years, but a few good years do not equate to recovery of wild sockeye.  In 2007, only four sockeye reached their spawning grounds in Idaho’s Redfish Lake.  In the mid 1950’s, sockeye returns to Redfish Lake totaled as high as 4,300.

•    Since the completion of the lower Snake River dams, wild Snake River steelhead have never reached their intended recovery target of 54,000 fish.

•    Just prior to the completion of the lower Snake River dams, wild Snake River fall chinook populations reached about 30,000.  Since then, these fish have plummeted by more than 90% and now teeter below their recovery target of 3,000.

•    It is clear to scientists that anything close to status quo river operations will be insufficient to achieve recovery of Snake River salmon and steelhead. The only measure that’s been demonstrated capable of recovering these fish is lower Snake River dam removal:

==>    The 1998 PATH (“Plan for Analyzing and Testing Hypotheses”) report concluded that within 24 years, partially removing the lower Snake River dams has an 80 percent and 100 percent probability, respectively, of recovering Snake River spring/summer chinook and fall chinook. The report also stated that fish barging programs, either current or maximized, have less than a 50 percent probability of recovery. Regardless of assumptions made or model used, dam removal was always the highest-ranked recovery option, and the one with the least amount of outcome uncertainty. [Marmorek, D.R., C.N. Peters and I. Parnell (eds.) 1998.  PATH final report for fiscal year 1998.  December 16, 1998]

==>    “[B]reaching the four lower Snake River dams would provide more certainty of long-term survival and recovery than would other measures.” [NOAA Fisheries. 2000 FCRPS Biological Opinion, 9-5]

==>    “In contrast to the uncertainty of success from the removal of hydro projects in other portions of the basin, the benefits to Snake River stock survival and recovery would be assured with the removal of the lower four dams on that system…” [Western Division, American Fisheries Society. Review Comments on the 2004 Biological Opinion Remand on the Operation of the Federal Columbia River Power System and 19 U.S. Bureau of Reclamation Projects (2005).]

==>    “As your administration goes about finalizing this draft, it is our sincere hope that politics will not be allowed to overshadow the predominance of scientific evidence pointing to the harmful biological impacts of federal dams along the Columbia and Snake rivers.  All available scientifically sound mitigation options (including, but not limited to, the partial removal of the four lower Snake River dams) must receive equal and impartial consideration as part of any comprehensive plan to restore wild salmon and steelhead.” [260 scientists from across the nation in a November 23, 2004, letter to President Bush regarding draft 2004 BiOp.]

==>    “Based on our assessment, a recovery strategy for Snake River spring/summer chinook salmon that relies largely on stream restoration to mitigate for known mortality attributable to current conditions imposed at other life stages (e.g., juvenile migration through hydroelectric dams) is highly unlikely to prove effective.”  [Budy, Phaedra, and Howard Schaller. Evaluating Tributary Restoration Potential for Pacific Salmon Recovery, Ecological Applications, 17(4), 2007 at 1081.]

In order to restore Snake River salmon populations to sustainable numbers, scientists have determined that they must consistently return adults to the uppermost Snake River dam, Lower Granite, at a minimum rate of 2% to 6%. Since 1975 when the eight dams (four on the lower Columbia River and four on the lower Snake River) were completed, return rates have only rarely exceeded the 2 percent survival minimum. From 1994 to 2004, they ranged from 0.35 to 2.5 percent, exceeding 2 percent in just a single year.

An extensive modeling effort completed in 2000 analyzed of the causes of mortality for Snake River salmon. The model demonstrated that the four lower Snake River dams were the most significant factor preventing recovery. The cumulative effect of eight dams on the lower Columbia and lower Snake Rivers is too much for salmon survival and if the four dams on the lower Snake were removed (cutting the total number of dams Snake River stocks face in half), these salmon can rebound to healthy levels.

More recent studies also show that populations of other Columbia Basin salmon that migrate through four or less dams and reservoirs, such as those from the Yakima and John Day rivers are performing significantly better than those from the Snake river. Those populations, like the Snake, also encounter mortality as a result of habitat destruction, harvest, hatcheries, predators and ocean conditions, but they are not imperiled. The difference lies in the number of mainstem dams they encounter. A key benefit for Snake River populations is the amount of high quality habitat they have that is not found in the other Columbia basins.

As a result of this extensive research, hundreds of federal, state, tribal and independent scientists have concluded that removing the four lower Snake River dams is the best and perhaps only means to protect these fish from extinction and recover healthy populations.

Share This