Think of all sorts of Pacific Salmon varieties including the endangered California Steelhead Trout species. But there's more. In the deserts southwest historically there were once large six foot long native fish once called the "White Salmon" (Colorado Pikeminnow) & the recovering Razorback Sucker. What do all these native fish have in common ? They desparately need meandering river floodplains
|Image - Carson Jeffres|
|SierraClub.org - July 16, 2012|
Of course there have been times (like the recent 1016/17 winter rainy season) when wetter than normal rainfall events have caused the rivers near the delta region to burst these levees in numerous places and reclaim former territories which are now towns, cities and other farmlands. This ends up in the News and the Army Corps of Engineers are called back to the reign in the power of Nature, saddle break it and force it to do what mankind wants and needs it to do. Very little of human infrastructure actually works with Nature instead of against it. Unfortunately humans are learning (too late) the correct course to take, but sometimes things in many areas are just permanently lost. There's no going back. But maybe with a few exceptions.
|Image - Yolo County Flood Control - 1993|
Here's a prime example above of those horrific flooding events in California's Central Valley back in 1993. Traditionally, almost the entire valley flooded in one way or another. This only happens now after long periods of rainy years where many of the reservoirs overflow their spillways and rivers run again freely with nothing to really block their former historical flow. If the flow is intense enough and more rains come, then breaches in these levees like the one above are common. Take a look at an article about a research study from U.C. Davis where solutions to Salmon decline have been found in rasing them in former floodplains.
The Solution to Restoring the Native Fish populations is restoring the Floodplains
|Photos by Jacob Katz|
|Image - Plos.org|
Using Rice fields as floodplain Nurseries“This study demonstrates that the farm fields that now occupy the floodplain can not only grow food for people during summer, but can also produce food resources and habitat for native fish like salmon in winter,” said lead author Jacob Katz of California Trout. “Our work suggests that California does not always need to choose between its farms or its fish. Both can prosper if these new practices are put into effect, mimicking natural patterns on managed lands. By reconnecting rivers to floodplainlike habitat in strategic places around the Central Valley, they have the potential to help recover endangered salmon and other imperiled fish populations to self-sustaining levels,” said Ted Sommer, lead scientist for the California Department of Water Resources and a co-author on the study.
Using Rice Fields as FloodplainsSince 2012, a team of scientists has been examining how juvenile salmon use off-channel habitats, including off-season rice fields. The experiments provide evidence that rice fields managed as floodplains during winter can create “surrogate” wetland habitat for native fish. The team suggests that shallowly flooded fields function in similar ways to natural floods that once spread across the floodplain, supplying extremely dense concentrations of zooplankton — an important food for juvenile salmon. Foraging on these abundant and nutritious invertebrates, the young salmon grow extremely quickly, improving their chances of surviving their migration to sea and returning in three to five years as the large, adult fish. Take note of the succees above of the fish size after being released within the rice field for a month. Representative juvenile Chinook salmon before (top) and after (middle) rearing for six weeks on the Knaggs Ranch experimental agricultural floodplain on Yolo Bypass. Bottom picture is of a tagged Knaggs fish incidentally recaptured in a rotary screw trap in the Yolo Bypass Toe Drain 13 miles downstream of the release site four weeks after the termination of the experiment. These small fish have no real chance of survival in a large river channel. Too many predators in the deeper river and not enough food trsources for them as would be the case in large shallow bodies of water where the zooplankton and insects thrive in warmer shallow waters.
Update (March 7th 2018)
Jacob Katz, with California Trout, says growing bugs in rice fields could be part of the solution for boosting salmon populations in rivers statewide. 😀
|Image - Ezra David Romero/Capital Public Radio|
Some other articles and references to this floodplain restoration concept to save Salmon and still allow commercial farming
Studies show the rice-field fish are larger, healthier and more robust than those in the river at the same age
|Image - Biographic|
So many of the native species of Colorado River basin native fish have disappeared for the very same reasons that have troubled the Salmon. Some are making a comeback and their story is not so dissilmilar to the Salmon rebound of California. The native fish above is the Razorback Sucker, but it itself is not the top predator. That would be the Colorado Pikeminnow (Ptychocheilus lucius) which ranged throughout the Colorado Drainage Basin as far south as the San Pedro River in southeastern Arizona into Mexico where old west historical accounts of six foot long fish were said to be common. In fact it could rival any large Salmon, even called at one time by the common name, White Salmon. But the deeper waters of the modern Colorado River which has been controlled by dams and channelization to keep it from flooding into former floodplains has hurt the reproduction efforts of many of the native fish which once dominated the river. Below is the story of the Razorback Sucker as seen in the picture above.
|Image - Biographic|
|Image - Biographic|
|Image - Biographic|
|Image - Biographic|
During our second day on the river, we pulled over to run our seines along a cobble bar. Nothing. Healy knelt to inspect the lifeless rocks. “In every other river, that cobble would be covered with caddis and mayflies and all kinds of algae,” he said glumly. “Here you don’t see anything because these huge tidal fluctuations leave it dry half the time.”
Even in the pre-dam era, Healy added, the Grand Canyon’s tight confines would have challenged larval razorbacks, which prefer to grow up in wide, shallow floodplains. What little habitat the canyon had once afforded, hydropeaking now erodes and dries out. “Razorbacks need warm, stable habitats full of food to get out of that larval stage,” Healy said. “They’re not getting that here.”
|Photo: Michael Short, The Chronicle|
|animated illustration - fcps.edu|
|Image - Ben Kiefer/UDWR|
|Image - Tom Teske & Google Earth|
|Image - Tom Teske|
|Image - Tome Teske|
These traps above are some other unique fish traps on the western edge of ancient Lake Cahuilla further south in Imperial county and are radically different from those of the Indio fish traps further north. Certainly the stones are much different. Altogether they have discovered around 69 of these traps on the shallow flats. I've posted an example of a common native American fish trapping basket that may have been close to what the Cahuilla would have built and used. Interestingly they have found the bones of native the Colorado River fish down here as well. Ninety-eight percent of the fish bones found at these archaeology sites are bonytail chub and razorback sucker which we discussed above. Both of these fish thrived in the warm, productive, plankton-rich environment of Lake Cahuilla. Remember, such shallows afforded these tiny delicate babies an opportunity to fatten up and move upwards in the food chain where insects would have become part of their diet. The reeds and other tules would have offered protection from predators, though many would have become food sources for many other lifeforms like birds. Still once big enough, they would have moved out into deeper water only to become prey for the top predator, the Colorado Pikeminnow. Also something else to ponder, with open access from the outflow of lake Cahuilla south of Mexicali to the Sea of Cortez by means of an extremely expansive delta, who knows what else may have entered the lake from the sea at one time. Perhaps the endangered almost extinct Vaquita porpoise and other fish we know almost nothing about. Some fish do migrate from sea to fresh water and back again. There is so much we will never know. But floodplains play major roles if only people will utilize them again. Fortunately the present system as it stands now has no future. Only then will things heal to the point of recovery and improvement far better than they were before.
What was once the Colorado Delta Floodplain once was (1905) and what it is today (2017)
|Image - National Fish and Wildlife Foundation|