Why are there so few salmon left?
There are many reasons for the decline in salmon populations. Logging an area around a stream reduces the shade and nutrients available to the stream and increases the amount of silt or dirt in the water, which can choke out developing eggs. Dams cause fish to die from the shock of going through the turbines and from predators that eat the disoriented fish as they emerge from the dam. Overfishing is another source of death that can contribute to the decline of salmon. The weather affects the amount of food that is available to salmon in the ocean. Pollution and disease have also contributed to population declines.
Learn more: Questions and Answers about Salmon
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Juvenile salmonid monitoring in the White Salmon River, Washington, post-Condit Dam removal, 2016
Condit Dam, at river kilometer 5.3 on the White Salmon River, Washington, was breached in 2011 and removed completely in 2012, allowing anadromous salmonids access to habitat that had been blocked for nearly 100 years. A multi-agency workgroup concluded that the preferred salmonid restoration alternative was natural recolonization with monitoring...
Jezorek, Ian G.; Hardiman, Jill M.
Preliminary evaluation of the behavior and movements of adult spring Chinook salmon in the Chehalis River, southwestern Washington, 2014
Recent interest in flood control and restoration strategies in the Chehalis River Basin has increased the need to understand the current status and ecology of spring Chinook salmon (Oncorhynchus tshawytscha). Spring Chinook salmon have the longest exposure of all adult Chinook salmon life histories to the low-flow and high water temperature...
Liedtke, Theresa L.; Hurst, William R.; Tomka, Ryan G.; Kock, Tobias J.; Zimmerman, Mara S.
Development of a study design and implementation plan to estimate juvenile salmon survival in Lookout Point Reservoir and other reservoirs of the Willamette Project, western Oregon
Survival estimates for juvenile salmon and steelhead fry in reservoirs impounded by high head dams are coveted data by resource managers. However, this information is difficult to obtain because these fish are too small for tagging using conventional methods such as passive-integrated transponders or radio or acoustic transmitters. We...
Kock, Tobias J.; Perry, Russell W.; Monzyk, Fred R.; Pope, Adam C.; Plumb, John M.
Survival of juvenile chinook salmon and coho salmon in the Roza Dam fish bypass and in downstream reaches of the Yakima River, Washington, 2016
Estimates of juvenile salmon survival are important data for fishery managers in the Yakima River Basin. Radiotelemetry studies during 2012–14 showed that tagged juvenile Chinook salmon (Oncorhynchus tshawytscha) that passed through the fish bypass at Roza Dam had lower survival than fish that passed through other routes at the dam. That study...
Kock, Tobias J.; Perry, Russell W.; Hansen, Amy C.
Behavior and movements of adult spring Chinook salmon (Oncorhynchus tshawytscha) in the Chehalis River Basin, southwestern Washington, 2015
Recent interest in flood control and restoration strategies in the Chehalis River Basin has increased the need to understand the current status and ecology of spring Chinook salmon. Based on the extended period between freshwater entry and spawn timing, spring Chinook salmon have the longest exposure of all adult Chinook salmon life histories to...
Liedtke, Theresa L.; Zimmerman, Mara S.; Tomka, Ryan G.; Holt, Curt; Jennings, Lyle
Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington
A multiyear radiotelemetry evaluation was conducted to monitor adult steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) behavior and movement patterns in the upper Cowlitz River Basin. Volitional passage to this area was eliminated by dam construction in the mid-1960s, and a reintroduction program began...
Kock, Tobias J.; Ekstrom, Brian K.; Liedtke, Theresa L.; Serl, John D.; Kohn, Mike
Estimating juvenile Chinook salmon (Oncorhynchus tshawytscha) abundance from beach seine data collected in the Sacramento–San Joaquin Delta and San Francisco Bay, California
Resource managers rely on abundance or density metrics derived from beach seine surveys to make vital decisions that affect fish population dynamics and assemblage structure. However, abundance and density metrics may be biased by imperfect capture and lack of geographic closure during sampling. Currently, there is considerable uncertainty about...
Perry, Russell W.; Kirsch, Joseph E.; Hendrix, A. Noble
Salmon redd identification using environmental DNA (eDNA)
IntroductionThe purpose of this project was to develop a technique to use environmental DNA (eDNA) to distinguish between redds made by Chinook salmon (Oncorhynchus tshawytscha) and redds made by Coho salmon (O. kisutch) and to distinguish utilized redds from test/abandoned redds or scours that have the appearance of redds. The project had two...
Pilliod, David S.; Laramie, Matthew B.
Seventy-five years of science—The U.S. Geological Survey’s Western Fisheries Research Center
As of January 2010, 75 years have elapsed since Dr. Frederic Fish initiated the pioneering research program that would evolve into today’s Western Fisheries Research Center (WFRC). Fish began his research working alone in the basement of the recently opened Fisheries Biological Laboratory on Lake Union in Seattle, Washington. WFRC’s research began...
Wedemeyer, Gary A.
Elwha River dam removal-Rebirth of a river
After years of planning for the largest project of its kind, the Department of the Interior will begin removal of two dams on the Elwha River, Washington, in September 2011. For nearly 100 years, the Elwha and Glines Canyon Dams have disrupted natural processes, trapping sediment in the reservoirs and blocking fish migrations, which changed the...
Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.
Approach, passage, and survival of juvenile salmonids at Little Goose Dam, Washington: Post-construction evaluation of a temporary spillway weir, 2009
This report describes a study of dam passage and survival of radio-tagged juvenile salmonids after installation of a temporary spillway weir (TSW) at Little Goose Dam, Washington, in 2009. The purpose of the study was to document fish passage and survival when the dam was operated with the TSW in place. Spillway weirs are one of several methods...
Beeman, J.W.; Braatz, A.C.; Hansel, H.C.; Fielding, S.D.; Haner, P.V.; Hansen, G.S.; Shurtleff, D.J.; Sprando, J.M.; Rondorf, D.W.
Impacts of Low-Flow and Stream-Temperature Changes on Endangered Atlantic Salmon - Current Research
Recent climate studies in New England and the northeastern United States have shown evidence of physical changes over time, including trends toward earlier snowmelt runoff, decreasing river ice, and increasing spring water temperatures. A U.S. Geological Survey (USGS) study funded by the National Global Warming and Wildlife Science Center will be...
Dudley, Robert W.; Hodgkins, Glenn A.; Letcher, Benjamin H.
In Hot Water: Climate Change is Affecting North American Fish
Climate change is already affecting inland fish across North America -- including some fish that are popular with anglers. Scientists are seeing a variety of changes in how inland fish reproduce, grow and where they can live.
Community flood protection may also help endangered salmon to thrive
Building a river setback levee to reduce the risk of flood for a community may also help endangered fish species to thrive, according to the results of a novel computer model reported by the U.S. Geological Survey.
Endangered Salmon Population Monitored with eDNA for First Time
CORVALLIS, Ore. — Scientists from the U.S. Geological Survey and Washington State University have discovered that endangered Chinook salmon can be detected accurately from DNA they release into the environment. The results are part of a special issue of the journal Biological Conservation on use of environmental DNA to inform conservation and management of aquatic species.
New Method Monitors Riverbed and Flows to Protect Spawning Salmon
USGS scientists took high-tech sensors typically found in devices such as smart phones and embedded them into a new method to monitor riverbed movements that can help protect spawning habitat for endangered salmon. Developed in cooperation with Seattle Public Utilities for the Cedar River, the new method is published in the Journal of Hydrology.
Wild Atlantic Salmon Found in New York's Salmon River
Scientists recently discovered wild young Atlantic salmon in New York's Salmon River. This is the first time in more than a century that salmon produced naturally in the wild have been found in what was once New York's premier salmon stream. Forty-one wild Atlantic salmon were collected in June and July. All of the salmon were under one year old and ranged in length from about 2 – 2.5 inches.
Removal of Obsolete Forest Roads Can Reduce Erosion and Sediment That Impair Salmon-bearing Streams
Removing abandoned forest roads and restoring the natural characteristics of slopes and stream channels in the Redwood National and State Parks in northern California have substantially reduced the delivery of sediment to salmon-bearing streams, according to a research geologist with the U.S. Geological Survey.
Acoustic-tagged juvenile Chinook salmon being released
Acoustic-tagged juvenile Chinook salmon being released.
An Alaskan Sockeye Salmon. USGS photo gallery. BLM photo.
Bacterial Kidney Disease in a spring Chinook salmon
A Spawning Coho Salmon
Coho salmon fins just above water surface. Female coho select breeding sties based on specific characteristics that offer protection and desired habitat for juveniles. Photo courtesy of Steven Clark, BLM
PubTalk 2/2015 — Undamming Washington's Elwha River
by Amy East USGS Research Geologist
- Hear about river response to the largest dam removal in history.
- Causing disturbance as a means of restoration: how well does it work?
- Will legendary salmon runs return?
Atlantic Salmon (Salmo salar)
Zoe Zyollewski handles an adult Atlantic salmon caught in the Connecticut River.