A Journey of Ten Million Years...the Salmon of the Sierra Nevada

Chinook Salmon attempting to enter the fish ladder at Camanche Dam on the Mokelumne River

They've been coming here for at least ten million years. Every year, without fail. The lands changed, but still they came. If one waterway was blocked, they eventually found another. Sometimes they were isolated, and could never return to the sea, but they survived anyway. They are the salmon and trout of the Sierra Nevada.

Stanislaus River at Knight's Ferry

Anadromous fish are those that live much of their lives in the oceans, but which return to freshwater streams to reproduce. One might wonder why they would have such a complicated breeding scheme. In all likelihood, it had to do with the survival of the young fish. Rivers and streams tend to offer more hiding places than open ocean, and the young have a chance to grow large enough to survive. The most familiar of these fish are the various species of salmon and Steelhead Trout. I had several opportunities to view the November migration of the Chinook Salmon this week on three different rivers: the Mokelumne, the Tuolumne, and the Stanislaus.

In historical times, the fish ranged far into the interior of the Sierra Nevada and Cascades Range, being stopped only by cascades and waterfalls too high for them to jump. They numbered in the millions. As European and American colonizers replaced the Native Americans across the state, the fish began a steep decline.

One of the first and worst events was the Gold Rush of 1848. Miners tore up miles and miles of river gravels and disrupted the flow of the rivers with their placer mines (sluices, long-toms, and cradles). Hydraulic mines (water cannons) ripped away billions of cubic yards of gravels from the hillsides and choked riverbeds with egg-smothering silt and clay. Vast amounts of water were diverted from river headwaters to feed the hydraulic mines through a system of flumes and pipelines.

Somehow the fish survived this onslaught, but then something more insidious happened. The dam-makers arrived in the late 1800s and early 1900s to build reservoirs to divert water for irrigation purposes. The dams themselves were barriers to the upstream movement of the fish, but even worse was that water diversions left the rivers to small and warm for their survival. The mega-dams were constructed in the 1960s and 1970s, diverting even more water. One river, the San Joaquin, ceased to flow most years over a stretch of about sixty miles. By the time the last dam was built, more than 95% of the historical breeding grounds for the fish had been made inaccessible to their migration (see the map below).

The blue portions of the rivers have salmon. The historical range is shown in black. Source: https://noaa.maps.arcgis.com/apps/MapJournal/index.html?appid=ceebefd9685143daa5bf30d5a7e0c7fa

Millions of years ago, this landscape was much different. The Sierra Crest was lower than it is today, but the summit region was covered by volcanic complexes not unlike the Lassen Peak complex and other parts of the Cascades. Periodic eruptions sent steaming lahars (volcanic mudflows) down the river canyons and onto the floor of the Great Valley (which may have actually been a shallow sea in this area). The rocks from this time period, 5 to 12 million years ago, are called the Mehrten Formation and they can be found throughout the Mother Lode foothills.

The Mehrten Formation has yielded up a treasure trove of fossil species. At Turlock Lake fossils were found of Giant Tortoises and Oncorhynchus rastrosus, the Spike-toothed Salmon. These remarkable salmon were as long as eight feet. They apparently used their "tusks" to fight for territory. Otherwise their lives were similar to the salmon of today. The riverbanks were populated by horses, camels, bison, antelope, giant ground sloths, mastodons, and carnivores, including the ancestors of the bears and wolves. The woodlands were dominated by sycamore and oak. For an excellent overview of the fossil record, check out the technical article by Sankey, Biewer and others, or read their excellent book The Giant Spike-Toothed Salmon and Other Extinct Wildlife of Central California.

Oncorhynchus rastrosus, the Giant Spike-toothed Salmon. Artist: Jake Biewer

Erosional processes steal nutrients from the land and carry them to the sea. It has been remarked that salmon and other anadromous fish return the gift. After they fight their way up the streams and rivers, and after they lay and fertilize their eggs, the fish die. Their bodies provide food for a host of carnivores and scavengers. Long before I found any fish in the Mokelumne River the other day I sensed the lurking presence of several dozen Turkey Vultures. I wasn't actually thinking about fish at that moment, but wondered why so many vultures were hanging around the river.

Moments later the reason was clear, as many were already feasting on the dead fish. The alert eyes that followed the movement of the fish are of an ancient lineage as well. Turkey Vultures are the most common of the avian scavengers, but their ancestors and Condor relatives patrolled these rivers millions of years ago.

These fish have survived for at least ten million years, and it has taken only a century and a half to threaten their very existence. Even now intense controversy follows the negotiations over how much water to devote to agriculture and how much to preserve the future of the salmon and the entire ecosystem that they inhabit. It's not a fish versus people proposition as some have portrayed it. It is a larger question of whether we want to preserve healthy river habitats for clean water, a diverse ecosystem, and for our own recreation and inspiration. Agricultural interests in the drainage of the San Joaquin showed in the 1940s that they were more than willing to destroy a river to apportion every drop of water. Things began to change in the 2000s as agreements were reached to restore flows to the lower river and bring back viable populations of Chinook Salmon. I hope we can be as wise in the other water conflicts around the San Joaquin Valley.

These videos are from the Mokelumne River below Camanche Reservoir, the end of the road for the Chinook Salmon. I had never visited the area before, so I was exploring the trails at the day use area below the fish hatchery. There were lots of fish in the river, and large numbers of them were struggling to break through the gates of the fish ladder, which was closed. I followed the fish ladder into the hatchery grounds, wondering if it actually provided access to the reservoir, but it didn't. It led to holding ponds that were already full of salmon. When the fish are ready, the eggs are harvested and fertilized, providing the stock for the hatchery. The young fish are later released into the river at the hatchery and other locations downstream.



These hatcheries are one way of dealing with the devastating loss of habitat for the salmon, but it seems it would be better if we could provide access to their ancestral breeding grounds upstream. I don't claim any expertise in these matters, but there have to be better answers than what we see happening today. They've been here for at least ten million years, and deserve a chance to be around for a few more.

One of California's Most Precious and Endangered Ecosystems: Riparian Oak Woodlands

Sunset at Caswell Memorial State Park

Ask people who know California what ecosystem has declined in area by more than 90%, and chances are they will answer "the Redwood forests". And they would be right. But given that there were once millions of acres of Redwood forests, it is also true that there are still a few large wilderness areas in the Redwoods, including a national park and many state parks. 

The Stanislaus River in Caswell State Park

If they think a little harder, they will answer "and also the prairies and grasslands of the Great Valley", and they will also be right. Almost all the native grasslands have been co-opted by agriculture, and that is kind of a shame, because the losses are continuing today as "hedge-fund" almond orchards are eating up tens of thousands of acres of grasslands with no secure source of irrigation water.

As they think more deeply, and develop a sad look because they don't like the direction these thoughts have gone, they will answer "and also the riparian oak woodlands". And they will once again be sadly right. The Great Valley once had hundreds and hundreds of miles of dense woodlands along the many rivers that flow out of the Sierra Nevada and into San Francisco Bay. Most of those woodlands have disappeared as levees were built, floodplain farms were planted and rivers were dammed (damned), cutting off the flow of the water. Precious few areas remain of these gloriously chaotic forests.

We spent the afternoon in one of the small remnants of these riparian (river) forests. Caswell Memorial State Park preserves 258 acres (about 2/5 of a square mile) of woodlands along the Stanislaus River near Ripon and Modesto. It's been developed at one end into a campground and picnic area, but the rest is managed as a de facto wilderness area, traversed only by a few trails, and consisting mostly of dense oak forest with an impenetrable undergrowth of shrubs and bushes (including a lot of poison oak, which discourages off-trail travel.

A "slough", or abandoned river meander in Caswell Memorial State Park

It's a popular summer destination for the locals, with a nice picnic area and a sandy beach along a slow moving stretch of river. During weekdays, many local schools take their kids on field trips, but on this late Friday afternoon we had the entire park to ourselves. Not a single other person in either parking lot. We happily wandered along some of the trails as the sun sank low onto the horizon, which wasn't visible because of the dense forest (see that top picture).

The park was once the home of the Yokuts people, but their populations were decimated after European contact. The Spanish missions, smallpox, malaria, and war with the Mexican Army eventually ended their existence in this region. The Stanislaus River is named after Estanislao, a Native American who led a rebellion against the Mexicans in 1829.  Decades later the lands were purchased by Thomas Caswell, and in 1950 the land was given to the state of California to preserve the woodlands.

Despite its small size the park preserves the only known natural habitat of the Riparian Brush Rabbit (Sylvilagus bachmani riparius), a subspecies of the Cottontail.  The original counts in the early 1990s suggested that only 200 or 300 of the rabbits remained, but the floods of 1997 were catastrophic, and only a few seemed to have survived in the park. Some were later found living in the San Joaquin Delta area, and a small population has been established at a ranch just downstream. Many of the rabbits have been captive-bred, trying to ensure their survival.

We might have been alone in the human sense, but the trees were alive with birds. They were mostly small and constantly moving so we weren't particularly successful in getting photographs, but we saw Ducks, Egrets, Juncos, Warblers, Starlings, Flickers, Vultures, and Hawks (and many others we couldn't identify), and we heard Sandhill Cranes in the near vicinity.

There were more than a dozen Turkey Vultures roosting in the trees above the river. I admit it was a little bit creepy having them all staring at us...

I was also lucky enough to catch one fairly sharp shot of a Northern Flicker, a species of woodpecker, in the trees above us. I heard it before I saw it...

Caswell Memorial State Park is a special place, well-loved by many people in the local region. Given that most of them see it when the weather is hot, the picnic areas crowded, and the grass dead and brown, they would have been surprised at the serenity of the place this afternoon. It's a great place to see what the valley was once like, and still could be today, if we continue our vigorous efforts at reclaiming some of the wetlands for nature.

Want a Wilderness Experience in Zion Canyon? Go Where the Trams Go.

Not where they stop, mind you, but where the trams go. Zion National Park underwent a huge change in 1997 when the park service closed the upper canyon of Zion to private vehicles and instituted a system of free tramways. The change brought an end to my favorite activity of night hiking in the upper canyon, and it at first seemed inconvenient when dealing with large student groups. But it didn't take me long to deeply appreciate the changes that came about in the upper canyon as a result.

For one, the animals became far more easy to see. On summer days, every available parking spot and pullout along the road would be filled with people, and the animal life would simply hide out. Without the constant commotion, animals felt more comfortable being out, and the tram rides now offer chances to see rabbits, deer, coyotes, foxes, and turkeys, while the tram drivers report seeing other more rare animals like mountain lions and badgers.

My recent trip to Zion afforded me some extra time to explore some new places, and I took the opportunity. The day started with a normal tourist target, the Gateway to the Narrows and the Riverside Walk. It is pretty much the most popular walk in the park, and is well worth seeing, even if it is crowded.

Zion Canyon is relatively wide in the lower reaches because the layers beneath the Navajo Sandstone are easily eroded, undercutting the high cliffs and causing rockfalls. It's where the Virgin River flows entirely in Navajo that the canyon gets incredibly narrow and very deep, with vertical walls reaching 2,000 feet above the river. The Riverside Trail is a paved ADA accessible trail that follows the narrowing canyon, ending after a mile at the entrance to the Narrows, where no trails are possible, but people can explore miles upstream as long as they don't mind getting wet numerous times.

Lots of water enters Zion Canyon from cliffside springs, and the hanging gardens can be very colorful. The Columbines are some of my favorite flowers. Don't worry about the feeling that you are being watched. It's either a Mountain Lion, or one of the Rock Squirrels. I don't which one is more menacing...

The trail is just gorgeous. But if the crowds bother you, there is a neat little secret for finding seclusion in the midst of the very busy national park. Like I said, walk where the trams go. Not where they stop, but where they travel between stops. You can walk along the road, or in many places a foot path follows close to the river. A tram will pass every 10 or 15 minutes, but that will be it for the motorized noise. I had two more hours to play with so I decided to walk as far down the canyon as I could.

I first passed the empty parking lot at the Temple of Sinawava, the end of the paved highway. I remember so many harried efforts to find parking for four vans on trips in years past, with hundreds of people hanging about, unwilling to give up their precious parking spots. Today it was quiet, because the moment the tram pulls up, people get out and immediately disappear up the trail.

Walking down the road, I was immediately struck by how unfamiliar the canyon looked. Walking is slow, giving one a chance to look at cliffs from new angles and new perspectives. I never saw this sort of thing from a car window.

The cliffs seem to change character every few hundred yards, with some cliffs sheer and unbroken, and others broken up by jointing. The air was fresh and the canyon bottom was still cool as the morning sun had not yet reached the floor of the gorge.

The emerald green cottonwood trees provided a strong contrast to the reds and browns of the canyon walls, and all of it was reflected on the waters of the Virgin River. Even the sound of flowing cascades felt unfamiliar and strange, but it was delightful as well.

Zion has been compared to Yosemite, only it's red and without the glacial origin. Maybe. I like to see each park on its own terms. Zion is a beautiful and stunning canyon.

I noticed a park tram stopped in an unlabeled pullout. It turned out to be a ranger tour, and I found out about an attraction in the canyon that is not on any of the park maps. It's called Menu Falls, and it is a delightful small waterfall just a few yards from the road. There is even a trail and platform for viewing, but to get there you either have to walk like I did or take the ranger tour. The name derives from the fact that early menus at the park lodge had a picture of the falls on the cover.

I happened upon a park ranger with a spotting scope looking for California Condors. The birds were once very much on the verge of extinction, down to just 22 individuals in the 1980s, but with a captive breeding program, they are making a comeback. Today there are more than 400, with more than 200 returned to the wild. The numbers may be close to their pre-European contact population. They are truly a relict Pleistocene creature, though, and would have been far more numerous during the Ice Ages, when the larger megafauna like giant bison and wooly mammoths would have provided much more food.

I'm sorry to tease you with the picture though. It's actually a Turkey Vulture. The ranger hadn't seen any this season yet. The upper canyon is also a good place to watch for Peregrine Falcons.

Around the next bend, the Great White Throne came into view. One of the tallest cliffs in Zion, it rises 2,300 feet above the valley floor. No trails reach the summit.

Zion is not known for Ancestral Pueblan ruins, but they are there, in a few spots. I had always seen one briefly through the car and tram windows over the years, but this walk was the first chance I ever had to photograph it. It appears to be a single granary, but was on a pretty steep cliff, so I didn't investigate further.

I reached the Weeping Rock tram stop, and time had run out. I'm pretty sure that next time I get the chance, I'll be walking down canyon from there. Who knows what else there is to discover?

A Bald Eagle, a Raven, and a Turkey Vulture Were Having Lunch Together...No, Really!

To my birding readers: how is this for an odd scene? It's the strangest bird picture I've ever taken, and the first ever of a bald eagle. I imagine they've been in our area for awhile, but until today I had never seen one south of Lake Tahoe. We were driving up through the Sierra Nevada foothills between the Gold Rush towns of Hornitos and Mariposa, and came across the group of scavenging birds. Mrs. Geotripper saw a pair of eagles in the Don Pedro Reservoir area two weeks ago, so I am wondering if they have moved into the region permanently.

I am also wondering if the coyote was shot (I certainly hope not poisoned) since I'm guessing that coyotes are too big to be attacked by the eagles. The scene was playing out in a large pasture allotment along Hornitos Road at an elevation of about 1,100 feet.