Why do salmon change color and die after they spawn?

Salmon change color to attract a spawning mate. Pacific salmon use all their energy for returning to their home stream, for making eggs, and digging the nest. Most of them stop eating when they return to freshwater and have no energy left for a return trip to the ocean after spawning. After they die, other animals eat them (but people don't) or they decompose, adding nutrients to the stream. Unlike Pacific salmon, Atlantic salmon do not die after spawning, so adults can repeat the spawning cycle for several years.

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How do salmon know where their home is when they return from the ocean?

Salmon come back to the stream where they were 'born' because they 'know' it is a good place to spawn; they won't waste time looking for a stream with good habitat and other salmon. Scientists believe that salmon navigate by using the earth’s magnetic field like a compass. When they find the river they came from, they start using smell to find...

How far do salmon travel?

Salmon first travel from their home stream to the ocean, which can be a distance of hundreds of miles. Once they reach the ocean, they might travel an additional 1,000 miles to reach their feeding grounds.

How long do salmon usually live?

Most salmon species live 2 to 7 years (4 to 5 average). Steelhead trout can live up to about 11 years.

When can salmon be seen migrating to their spawning area?

Most Pacific salmon can be seen migrating from spring though fall, depending on the species. Most adult Atlantic salmon migrate up the rivers of New England beginning in spring and continuing through the fall as well, with the migration peaking in June.

Why do salmon eggs come in different colors?

Salmon eggs (roe) range in color from pale yellowish-orange to dark reddish-orange. The color varies both by species and within species and is determined by water temperature, sediment composition, age, and other factors. The eggs vary in size from the tiny sockeye roe (average ¼ inch or 5.6 mm) to the large chum roe (average almost ½ inch or 8.3...

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...

How many species of salmon are there and how large can they get?

There are seven species of Pacific salmon. Five of them occur in North American waters: chinook, coho, chum, sockeye, and pink. Masu and amago salmon occur only in Asia. There is one species of Atlantic salmon. Chinook/King salmon are the largest salmon and get up to 58 inches (1.5 meters) long and 126 pounds (57.2 kg). Pink salmon are the...

Where are salmon most endangered?

Certain populations of sockeye salmon, coho salmon, chinook salmon, and Atlantic salmon are listed as endangered. Sockeye salmon from the Snake River system are probably the most endangered salmon. Coho salmon in the lower Columbia River may already be extinct. Salmon are not endangered worldwide. For example, most populations in Alaska are...

Are salmon endangered worldwide?

No, salmon are not endangered worldwide. For example, most populations in Alaska are healthy. Some populations in the Pacific Northwest are much healthier than others. These healthy populations usually occupy protected habitats such as the Hanford Reach on the Columbia River and streams of Olympic National Park.
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Date published: April 20, 2016

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. 

Attribution: Northwest
Date published: January 5, 2015

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.

Attribution: Ecosystems
Date published: June 6, 2013

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.

Date published: March 6, 2001

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.

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Brown bears (Ursus arctos) and Chum Salmon (Oncorhynchus)
December 31, 2017

Bear predation on salmon can be high in many Alaskan rivers.

Bear predation on salmon can be high in many Alaskan rivers.  Brown bears Ursus arctos and Chum Salmon Oncorhynchus keta are managed concurrently in McNeil River State Game Sanctuary by Alaska Dept. of Fish and Game to benefit the salmon, bears, commercial fishers, and provide unparalleled close-up bear viewing and photography opportunities for the public.

Brown bears (Ursus arctos) and Chum (Salmon Oncorhynchus)
December 31, 2017

Brown bears (Ursus arctos) and Chum (Salmon Oncorhynchus)

Bear predation on salmon can be high in many Alaskan rivers.  Brown bears Ursus arctos and Chum Salmon Oncorhynchus keta are managed concurrently in McNeil River State Game Sanctuary by Alaska Dept. of Fish and Game to benefit the salmon, bears, commercial fishers, and provide unparalleled close-up bear viewing and photography opportunities for the public. 

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Kasilof coho salmon with radio tag antenna in it's mouth
March 8, 2017

Radio-tagged Kasilof River coho salmon

Radio tagged coho salmon from the Kasilof River in Alaska

Alaskan sockeye salmon. Courtesy, BLM
June 28, 2016

Sockeye Salmon

Alaskan sockeye salmon. Courtesy, BLM

A Spawning Coho Salmon
December 31, 2015

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

Image: Young Atlantic Salmon
January 11, 2012

Young Atlantic Salmon

These two-day old Atlantic salmon were hatched at the USGS Tunison Lab and will eventually be released in Lake Ontario tributaries.

A new, sophisticated fish rearing facility in Cortland, N.Y. will help restore Atlantic salmon, bloater, and lake herring to Lake Ontario, strengthening the local ecosystem and economy.

To restore the population, young Atlantic

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Image: Salmon Are Carefully Released Using Buckets
September 1, 2011

Salmon Are Carefully Released Using Buckets

Thousands of young Atlantic salmon are being released into Salmon River in an effort to restore this diminished Lake Ontario fish population, extending the sport fishing season by at least two months in Oswego County, N.Y.

During fall 2011 and spring 2012, U.S. Geological Survey scientists will stock Beaverdam, Orwell, and Trout Brooks and the main stem of the

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Image: Scientists Release Altantic Salmon into Beaverdam Brook
September 1, 2011

Scientists Release Altantic Salmon into Beaverdam Brook

USGS Tunison Lab scientists Rich Chiavelli (left) and Emily Waldt (middle) hand a bucketful of young Atlantic salmon to Dan Bishop (right) of the New York State Department of Environmental Conservation for release into Beaverdam Brook at the state's Salmon River Fish Hatchery.

Thousands of young Atlantic salmon are being released into Salmon River in an effort to

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