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.
Learn more: Questions and Answers about Salmon
Related Content
How do salmon know where their home is when they return from the ocean?
How far do salmon travel?
How long do salmon usually live?
When can salmon be seen migrating to their spawning area?
Why do salmon eggs come in different colors?
Why are there so few salmon left?
How many species of salmon are there and how large can they get?
Where are salmon most endangered?
Are salmon endangered worldwide?
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.
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.
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.
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)
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.
...
Radio-tagged Kasilof River coho salmon
Radio tagged coho salmon from the Kasilof River in Alaska
An Alaskan Sockeye Salmon. USGS photo gallery. BLM photo.
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
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
...
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
...
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
...