CONTRIBUTE

Golden Gate National Recreation Area

Steelhead

Steelhead ESUs
Oncorhynchus mykiss

USDA Photo

Home >> Species >> Steelhead ESUs

Steelhead ESUs
Oncorhynchus mykiss

Steelhead are a unique type of salmonid. Unlike most other salmonids, Steelhead are iteroparous, which means they can spawn more than once during their lifetime.  Furthermore, individuals develop differently depending on their environment. While all O. mykiss hatch in gravel-bottomed, fast-flowing, well-oxygenated rivers and streams, some stay in fresh water all their lives. These fish are called Big Year Salmon Hike at Muir Woodsrainbow trout. The Steelhead that migrate to the ocean develop a much more pointed head, become more silvery in color, and typically grow much larger than the rainbow trout that remain in fresh water.
 
Steelhead can live for as long as 11 years and grow as large as 55 pounds.  They may spend as long as seven years in fresh water before migrating downstream to the estuaries as smolts and then into the ocean to feed and mature.  Their coloring is quite distinctive: from dark olive green on their backs shading to silvery-white underneath, they sport a pink racing stripe down the side.  They are able to tolerate a greater range of water temperatures than other salmon, which may explain their longevity.

The Endangered Species Act permits the federal government to protect imperiled species, subspecies, and "distinct population segments." The term "distinct population segment" is a term of art that allows the government to protect portions of an entire species before a particular threat or population decline becomes so severe that the entire species is placed in jeopardy. There are two federally protected distinct population segments of Steelhead in the GGNRA: the California Central Valley Steelhead DPS and the Central California Coast DPS.

California Central Valley Steelhead DPS

The California Central Valley steelhead DPS includes all naturally spawned populations of Steelhead in the Sacramento and San Joaquin Rivers and their tributaries, excluding steelhead from San Francisco and San Pablo Bays and their tributaries. They are thus transient in the GGNRA, passing through the Park's marine waters only when traveling from the ocean or to the Steelhead's natal spawning streams.

Although Steelhead are believed to be more tolerant than other salmonids to fluctuations in habitat conditions, Steelhead populations suffered major declines when large dams were built throughout California, destroying Steelhead spawning habitats. This population was protected as threatened under the Endangered Species Act in 1998, and this decision was affirmed in 2006.

 

Central California Coast Steelhead DPS

The Central California Coast Steelhead DPS includes all naturally spawned populations of Steelhead from the Russian River in Sonoma County through and including Soquel Creek in Santa Cruz County. This includes all Steelhead in San Pablo and San Francisco Bays. These Steelhead have several spawning streams in the GGNRA, particularly in Marin County.

The Russian River is the largest system in this DPS and probably contained the largest Steelhead population historically. Recent estimates indicate that the population in this river is only 15% of what it was 30 years ago. This may be indicative of the range-wide status of this Steelhead DPS. Although Steelhead remain fairly well distributed spatially throughout this DPS, impassible dams have cut off substantial portions of spawning habitat in some basins.

Conservation Action Item

Steelhead need cool, clean waters to reproduce successfully. Water diversions, dams, and water pollution are all lethal to their continued existence.

There is an action item for each Steelhead ESU that uses the GGNRA:

1. Central California Coast Steelhead DPS- Help with SPAWN's habitat restoration programs in Marin to keep the species' habitat thriving.

2. California Central Valley Steelhead DPS- Please urge your public officials to increase funding for National Parks such as the Golden Gate National Recreation Area, so that they can protect endangered species such as Steelhead through research, education, and restoration.

Trips

Blog

Please enter your comments for this article.

Name :
 
Email Address: (Not displayed with comment.)
 
URL: (Optional)
 
Comments:
 
Enter Image Characters Below:
  
 

Previous Comments

Posted by: Steve Price | 2008-06-04 16:49:13

Saw a fingerling swimming beside a Coho Salmon fingerling in the pools of Redwood Creek, Muir Woods. This is an easy walk and especially good early in the morning before the tourists arrive.