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Codornices Steelhead: Ghosts of the Winter Run By JOE EATON Special to the Planet

Tuesday March 28, 2006

A couple of weeks ago I got an e-mail message from Susan Schwartz, president of Friends of Five Creeks, about a recent sighting: two pairs of steelhead that had followed Codornices Creek in from the Bay, as far upstream as Masonic Avenue, where they appeared to be attempting to spawn. 

They were good-sized fish, 24 inches long, with the classic silvery coloration of this ocean-going variety of rainbow trout. The females were trying to dig redds—depressions in the streambed—for their eggs. Unfortunately, concrete rubble, which is all the steelhead had to work with, is not the best substrate for spawning. But you have to give them credit for making the effort. 

Emma Gutzler, Restoration Coordinator for the Urban Creeks Council, was there with her videocamera, and you can see a short clip of the event on UCC’s web site (, or on Friends of Five Creeks’ site ( 

Gutzler says this was the first documented sighting of spawning steelhead this far up Codornices. “Everybody knew we had resident rainbow trout there,” she says. 

But the largest trout recorded in a fish survey last fall were only nine inches long; the two-footers were definitely not there before the winter rains. They hung around for at least three days, after which a new bout of rain increased the turbidity of the creek and discouraged fishwatchers.  

What’s the difference between a steelhead and a regular rainbow? 

They belong to the same species, Oncorhynchus mykiss, but the taxonomy below the species level is fiendishly complicated. The basic distinction, though, is that steelhead, like their salmon relatives, spawn in freshwater and mature at sea. Fish that divide their time between fresh and salt water are called diadromous. Steelhead and 13 other California species, including sturgeon, striped bass, and some lampreys, are anadromous. 

Catadromous fish, like the eels of eastern North America and Europe, mature in streams and rivers and breed at sea—in the Sargasso Sea, in the case of the eels. California, as luck would have it, has none of these interesting and tasty fish. 

But we do have a half-dozen discrete populations of steelhead that are classified as evolutionarily significant units (ESUs, in conservation parlance). They’re all in the subspecies O. m. irideus, but each group is genetically distinctive enough to be treated separately for management purposes, although there’s apparently some gene flow among them. 

From north to south, steelhead ESUs have been described for the Klamath Mountains, the North Coast, the Central Valley, the Central Coast, the South/Central Coast, and the South Coast. Some of these populations are further divided into winter and summer runs, based on the timing of spawning. The steelhead in Codornices likely belonged to the Central Coast stock, all winter-spawners with an historic range from the Russian River to Aptos Creek in Santa Cruz County.  

Unlike Pacific salmon, steelhead may spawn more than once in their lives—up to four times if their luck holds. The mature males that accompany the females upstream meet competition from smaller precocial males called jacks that have spend only a few months at sea, and even smaller parr males that have never left their natal stream. 

The little guys, collectively known as sneakers, will try to fertilize the female’s eggs while the mature male guarding her is distracted. Schwartz and Gutzman said the steelhead in Codornices attracted smaller trout; they may have been sneakers, or they may have been looking for a snack. One fish’s progeny can be another’s protein. 

The whole steelhead-rainbow business is fraught with irony. Thanks to introductions, non-migratory rainbows are now found in previously troutless streams and lakes all over California, and on every continent except Antarctica. You can fish for rainbows in Hawaii, in Tasmania, on the Indian Ocean island of Reunion. But habitat loss—from urbanization, dams, diversions, flood control projects, agriculture—has brought the anadromous steelhead to the brink of extinction. 

The Central Coast population declined by 85 percent between 1960 and 1997, when it was finally listed as threatened by the National Marine Fisheries Service, and UC Davis biologist Peter Moyle says there must have been significant losses even before 1960 due to all the “insults to watersheds” over the previous 150 years. 

Creek activists have done heroic work in Codornices Creek and elsewhere to help the steelhead recover. As Schwartz says: “Nature will come back if we just open the door.”  

Volunteers have been restoring habitat along the creek for 15 years, and CALFED and the State Water Resources Control Board have funded a Codornices Creek Watershed Restoration Action Plan with steelhead in mind.  

It was something of a shock, then, when NMFS deleted Codornices and most of the Bay’s other tributaries from the critical habitat designated for the Central Coast steelhead last September. Only Alameda Creek made the final cut. 

UCC Executive Director Steve Donnelly responded to the proposed changes in March: “The conservation biology logic of wiping dozens of watersheds, including those which we have labored to revitalize over the past 20 years, from the scheme for recovering Central California Coast steelhead escapes us completely. When did ‘putting all your eggs in one basket’ make conservation biology sense?” 

The agency was unswayed. Its final rule described Codornices as having “low habitat quantity and quality, low restoration potential, no unique attributes, and small [steelhead] population size.” 

That also went for other East Bay streams, from Pinole to Suisun Bay, and for Sonoma and Marin watersheds. 

Critical habitat may be a moot issue if Richard Pombo’s hatchet job on the Endangered Species Act makes it through the Senate, of course. But it’s played a vital part in constraining destructive development on federal land, or where federal funding or permitting is involved.  

In any case, those steelhead didn’t know or care that the feds had written off their creek. It still smelled right to them. The door had been opened, and they came on in.