Genetics May Save Trout From Extinction


As far as fish stories go, this one has to rank right up there.

And it’s a story that’s been in the making for millenniums. Silver and blue and weighing up to 10 pounds, the southern steelhead trout is strong and swift and, by fishy standards, even smart and cunning.

For generations this beautiful fish not only has survived, but thrived, in an area infamous for its endless cycle of drought, fire and flood. To perform its signature act, migrating from ocean to upstream spawning grounds, the steelhead navigated an obstacle course through the creeks and rivers that once ran unhindered from Southern California’s mountains to the sea.

Sometimes the fish would slither across the sand in a few inches of water to reach a creek’s mouth. Once in the stream, it would dart under boulders and leap over small waterfalls. Anything to reach the place where it could spawn and produce the next generation of resilient steelhead.


No one knows just how many steelhead live in Southern California today. Some researchers say the fish, declared endangered last year, will soon be extinct. Others aren’t so sure.

“We’ve done everything we possibly can to eradicate these fish,” says Dennis McEwan, a fisheries biologist and steelhead expert with the California Department of Fish and Game. “But the steelhead are still there.”

The wildlife and scientific communities are now debating what to do about the southern steelhead, how to protect it and how to balance its needs against those of man. But this isn’t just the classic people-versus-nature story, though there’s plenty of that in this tale. The story of the southern steelhead is also a tale of genetics--genetics that might explain how all species evolve.

Southern steelhead are still here, most biologists say, because they evolved to beat the odds.


“These fish have had to be extremely flexible because of the [climate] in Southern California,” says Sara Chubb, a fisheries biologist with the Los Padres National Forest. “They are a hearty fish that can jump far, have a lot of stamina and stream smarts because, in order to survive, they have to make it to places with marginal habitat.”

That habitat once extended from the Santa Maria River near Pismo Beach down to Baja California.

Tens of thousands of adult steelhead once migrated from the Pacific to small streams in the mountains of northern Ventura County. They swam up the Santa Clara and Ventura rivers by the thousands, headed for Matilija, Sespe and San Antonio creeks in search of gravelly shoals to lay millions of eggs. Old-timers recount tales of whoppers hauled from local streams in the 1930s and 1940s.

Now, scientists estimate probably 200 or so continue to make the journey in Ventura County.

The steelhead’s range today is believed to extend no farther south than Malibu Creek, where a silt-choked dam blocks steelhead from migrating upstream.

Tens of thousands of years ago--no one is exactly sure when--there was an ancestral population of Pacific salmon. As the years passed, the population was separated as glaciers overtook the land, earthquakes pushed up mountains and other forces molded the Earth.

Eventually, these separated populations developed into various subspecies of Pacific salmon, such as Chinook and coho. The steelhead, which is actually classified as a salmon, also established its own niche in nature. But evolution hardly stopped there.

Different stocks of steelhead evolved, each unique to its particular habitat. And, within these stocks, another peculiar trait developed. Some steelhead are anadromous, meaning they are born in freshwater and later run to the sea. Others are non-anadromous, spending their entire lives in freshwater. These fish are known as rainbow trout.


“This is a species that has an enormous palette of life histories to choose from,” says Jennifer Nielsen, a biologist and geneticist with the U.S. Forest Service.

Steelhead evolved, in other words, to play by the hard rules Mother Nature set down in Southern California.

Then, people came along and the rules began to change.

Impassable barriers like dams cut off the headwaters where steelhead like to spawn. Pollution robbed the fish of clear water. Lagoons were drained or filled in, taking away the transition zone where steelhead make the chemical transformation to saltwater.

“The health of the species depends upon the health of the component parts,” says Rob Jones, a spokesman with the National Marine Fisheries Service. “If we lose more and more of those parts, the ability of the fish to survive will decline until we lose everything.”

Much has already been lost. Twenty-three stocks of steelhead trout have gone extinct this century, and another 43 (including the southern steelhead) face a moderate to high risk of extinction, according to the fisheries service. The reason: habitat loss and degradation.

The Santa Ynez River, near Solvang, was once considered to have the highest population of steelhead in Southern California. In fact, in 1944 the California Department of Fish and Game found approximately 1 million juvenile steelhead trapped in a drying portion of the river. Today, the number of adult steelhead in the Santa Ynez is probably less than 200.

Many biologists and ecologists express a guarded optimism that the southern steelhead will not be lost. It has survived this long, they say, and there is still good habitat left in Southern California.


The problem, however, is that the steelhead often can’t get to the habitat.

Solstice Creek is a small, perennial stream on National Park Service land flowing from the Santa Monica Mountains to Malibu. But a culvert under Pacific Coast Highway prevents steelhead from reaching it.

In Matilija Creek, in Santa Barbara and Ventura counties, there are wild rainbow trout stuck upstream behind the silted-up Matilija Dam. What would happen if these fish could get to the ocean? After 50 years, would they show anadromy and run to the sea?

Sespe Creek, north of Fillmore in Ventura County, is the last free-flowing major stream in Southern California. Steelhead once migrated 80 miles up the Sespe and, today, most of the creek lies within protected wilderness. But fish have difficulty reaching the Sespe because it drains into the Santa Clara River, which suffers from environmental problems.

“Those fish went to places you would never believe there were fish,” says Sara Chubb. “There seems to be something inherently bred in their genetics that makes them want to go further, to keep repopulating.”

Southern Steelhead’s Amazing Secret

Throughout most of this century, the decline in the number of steelhead in Southern California was of little concern to the populace and government alike.

After all, steelhead could always be found in the wetter climates of Northern California and the Pacific Northwest. In mighty rivers like the Klamath or the Rogue, a 30-pound steelhead could snap a man’s $1,000 fly rod in two. In these places, men line up elbow to elbow at river’s edge, hoping to hook a winter-run steelie and experience what one guidebook calls the “apogean angling experience.”

Conversely, the southern steelhead was thought to be a freakish, negligible population of strays from the north that, perhaps unfortunately, was doomed. Fishing regulations in Southern California were few and, often, unenforced. Besides, the sea and reservoirs offered more-plentiful angling opportunities.

Then, in 1994, came a remarkable--and controversial--discovery.

That year, Jennifer Nielsen, the forest service geneticist, used DNA fingerprinting technology to determine that southern steelhead had more genetic diversity than any other type of steelhead. Quite suddenly, southern steelhead were no longer a trivial presence.

“When the study came out, all hell broke loose,” says Nielsen. “I had calls from people asking if I was certain these were steelhead I had studied. These were fish just waiting for the door to open because genetically they had a lot to say.”

Like circles inside a tree stump, genetic diversity is believed to be a sign of age--the more genetic diversity a species has, the older the species is believed to be.

Nielsen and many other biologists believe this could mean that southern steelhead are the oldest steelhead of them all. Perhaps they are even native to the area (harsh environments are thought to produce genetic diversity).

This, in turn, could mean that all steelhead stocks evolved from southern steelhead or that southern steelhead may have repopulated northern areas following the last ice age.

“To keep every cog and wheel is the first precaution of intelligent tinkering,” wrote the naturalist Aldo Leopold, half a century ago. Leopold’s rule has since become the guiding principle in efforts to save endangered species.

Or, to put it another way, if you really want to save a species, save all its diverse parts. Because, one of those parts--like the southern steelhead’s ability to cope with warm water--just may be the key to adapting to something like global warming.

A Long-Closed Door May Someday Reopen

Many biologists believe steelhead never had a grip on Malibu Creek, so much as a loose grasp on it.

In the drought years, much of the creek probably dried up. Steelhead and rainbow trout may have survived in a few deep pools. Or, some may have sought refuge in the sea.

Other steelhead, too, likely perished.

More than anything, Malibu Creek was a wild, dynamic, ever-changing place. Until people began taming the land.

About 2.5 miles upstream from the ocean, Malibu Creek turns abruptly to the east and then enters a steep and narrow gorge. From the point of view of an engineer, this notch in the canyon walls was the perfect place to anchor Rindge Dam.

In 1926, the year Rindge Dam was completed, the entire lower section of Malibu Creek was a part of the 17,000-acre Rindge family ranch. The family needed water for its ranch, and the concrete arch dam--reinforced with railroad ties from the dismantled Hueneme, Malibu and Port Angeles Railroad--was the perfect solution.

But the dam had a problem: sediment. Within 40 years, the small reservoir behind the dam had completely filled with the heavy silt load Malibu Creek carries. The creek no longer backed up behind the dam, but instead flowed right over the top.

There has been talk of removing the dam for 30 years, but this September the talk turned serious when the Army Corps of Engineers said it would consider a feasibility study of modifying or removing Rindge Dam.

According to the corps, it’s a project that could take almost a decade to complete--if it does indeed go forward. Local sponsors will have to carry almost half the cost. And the price could be considerable: A 1994 federal study said removing the dam could cost at least $4 million, maybe even $17.5 million.

“The biggest thing we need to do is to reconnect those fish with their upstream habitats,” says McEwan. “If we can just work on that one thing, and if dams like that one are made passable, then the fish can take advantage of those good, wet years where there is a lot of flow. Right now it doesn’t matter, because they can’t get there.”

Malibu Creek has been dammed in four places, but biologists have deemed Rindge Dam as the most harmful to steelhead because it squeezes the fish into 2.5 miles of stream between the dam and the ocean. A 1990 study estimated that removing the dam and fixing three minor barriers would allow the steelhead to reach five more miles of upstream habitat, including two major tributaries--Cold Creek and Las Virgenes Creek.

After all these years, would steelhead swim above the dam if given the chance? If so, could the fish end up reaching suburbs like Calabasas and Agoura Hills--the last place most people would expect to see a 2-foot-long fish returning from the sea?

“I’m not aware of any data indicating steelhead were ever above Rindge Dam, but we consider the behavior of fish in other streams to form an opinion of what the fish might have done, and will do, in Malibu Creek,” says Anthony Spina, a biologist with the fisheries service. “It’s my opinion that any time we can open additional habitat for steelhead, we should.”

Perhaps the most intriguing thing about a recovery effort in Malibu Creek is this: There are 80,000-plus people living in the Malibu Creek watershed, and biologists see the creek as an opportunity to prove that people and fish can coexist. Helping the steelhead would provide incentive to further clean up the creek’s diminished water quality. There’s even talk of one day building a steelhead interpretive trail along Malibu Creek.

“I used to think it was fish versus people,” says McEwan. “Now, it’s fish versus funding. We don’t have to have wildlife in a park or zoo. We can make room for these creatures within our own environment.”

Steve Casey, who used to fish for steelhead in Malibu Creek before they were declared endangered, puts it differently.

“All my life, I’ve heard about the way California used to be,” says Casey. “Well, I’m sick of hearing it and I don’t want to tell my kids the same thing about Malibu Creek and the steelhead.”

If It’s Not Extinct, It Should Be

“Fifty years ago every live brook, runnel and stream that made a pretense of carrying some head of water though the summer drought had its quota of steelhead moving upstream.”

--from the book “Steelhead to a Fly,” written by Clark Van Fleet.

Almost a century after Van Fleet’s observation about steelhead in 1901, no one knows how many southern steelhead still exist. There are few people paid to look for them, and even when they do, the fish are hard to find.

But the one thing everyone agrees on is this: There are nowhere near as many steelhead as there used to be. Jennifer Nielsen points out that under the rules of traditional conservation biology, the southern steelhead trout should be extinct. Once the population of a species drops below a certain threshold, mortality outpaces reproduction and extinction is inevitable.

Yet, the southern steelhead has stubbornly resisted that rule.

In August, Anthony Spina, a marine fisheries biologist, went snorkeling in Topanga Creek. Steelhead were often caught in the creek in the 1960s and early 1970s. But no one had seen a steelhead in the creek since 1983, and many biologists thought water pollution had done them in.

Wading from pool to pool along the creek, Spina looked down and saw a 5-inch juvenile steelhead.

Later, when the soft-spoken and cautious Spina was asked about it, his answer was: “Interesting.”

Interesting, indeed, that the southern steelhead trout, at least on this one day and in this one place, was still there.

Times staff writer Gary Polakovic contributed to this story.


Saga of the Steelhead

Steelhead trout have a life cycle similar to salmon. The Southern California strain of steelhead has dwindled to nearly zero from a variety of factors, including loss of habitat due to water diversions, dams, urban development and pollution.

Steelhead are anadramous, meaning they are born in fresh water, migrate to the ocean and return to fresh water to spawn. Unlike most salmon, not all steelhead return to their native streams, and a small percentage of steelhead can spawn more than once. Steelhead that live their entire lives in fresh water are called rainbow trout

Life Cycle

Steelhead are nothing if not adaptable, and this is especially true of the southern strain, which has historically dealt with extreme changes in Southern California’s climate. Steelhead must wait until winter rains raise creek levels high enough to breach the sand bar that forms at the mouth of most creeks. In dry years, they may not even get the chance.

1. Female buries eggs several inches deep in nests in river gravel. Male fertilizes eggs, which hatch in 3-5 weeks and become “alevins.”

2. Surviving alevin, or fry, remain in stream’s deep pools to avoid predators, and feed on insects and crustaceans. 3. Fry turn into smolts--shedding scales and turning silver--and usually spend 1-3 years in river system. Smolts adapt to salt water by staying in estuary where fresh and salt water mix

4. Steelhead migrate to ocean and typically remain there for 1-3 years

5. When ready to spawn, steelhead use sense of smell to locate their birth streams. Female finds suitable spawning area and the process begins anew

Steelhead Trout

Size: In the past, full-sized adults in Malibu Creek measured to 20 inches in length. Northern strains can reach 40 pounds.

Coloring: A steel-blue color, which distinguishes them from the multi-hued rainbow trout.

Habitat and diet: Steelhead require cool, clear water. Malibu Creek is believed to be the southern strain’s southernmost location. At sea, adults are typically found close to ocean’s surface and prefer to eat squid, small fish and crustaceans.

Sources: National Marine Fisheries Service; “California Coast & Ocean”; “Field Guide to the Pacific Salmon” California Trout. Researched by JULIE SHEER/Los Angeles Times