Friday, June 23, 2017

Floodplain Farmlands Benefit Juvenile Western Native Fish

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 - July 16, 2012
Back in the 1970s, I was intrigued by an article from the Arizona Highways magazine article which told about a Native golden Apache Trout which almost went extinct were it not for the efforts of Biologists working with the Apache Indian Reservation. But they also referenced other native fish, even mentioning that some 35 different species of native fish once occupied the desert aquatic environments of Arizona. That was almost hard to believe. Like California, Arizona has dammed up it's rivers and channeled much of their watercourses to faciliate agriculture and urban sprawl. Take the river channel in photo on the right which has large tall levees on both sides to prevent the ancient floodplain from reappearing and reclaiming it's former territory. This area of Northern California is known as the Yolo By-Pass region where the floodplain is allowed to prevail once a year. Here below is a video of a very long elevated freeway section of Interstate 80 which allows the floodwaters to do their former inundation of the former wetlands landscape.

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

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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 Floodplains
Since 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
NPR: "A 'Floating Fillet': Rice Farmers Grow Bugs To Replenish California's Salmon" 
Some other articles and references to this floodplain restoration concept to save Salmon and still allow commercial farming Floodplain farm fields provide novel rearing habitat for Chinook salmon
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
The fingerlings here have been captured by the researchers using a seigning net along the shallows where small fingerlings would be located. While you look at this bag of small fish on the right, only four were actually Razorback Suckers. The others were Bluehard Suckers and Flannelhead Suckers. Both native and that is good thing, but their main goal was the Razorbacks. Apparently these Scientists captured both adult Razorback Suckers and larvae in the canyon, but they didn’t find any juveniles or sub-adults. Just mature adults and larvae. These adults were living in Lake Mead and moving up the canyon to spawn. But again, beyond finding the Razorback larvae, there were no larger juveniles which indicated a problem. 

Image - Biographic
The only way to tell Razorback Sucker larvae (at the bottom) from more common cousins like Bluehead Suckers (top) and Flannelhead Suckers (middle) is through a microscope, using diagnostics like the density of back speckles and muscle fibers. So the other sucker species were doing okay, just not the razorbacks. The Glen Canyon Dam made the Colorado River simultaneously more stable, by eliminating massive spring floods, and more volatile, by instituting unnatural tide levels in the river. By tides we are basically talking about higher and lower water levels fluctuating regularly, something unnatural to this river canyon. In the Arizona morning, millions of people in Phoenix and other desert cities flick on their lights and air conditioners, then the dam managers crank up flows through Glen Canyon’s hydroelectrical turbines to meet power demand. But then at night they power back the turbines. These water level fluctuations in the river are called hydropeaking, because they cause the river to rise and fall by several feet each day. This messes with the aquatic ecosystem's biological food supply, especially for the tiny fish. More on that in a moment. 

Image - Biographic
At several days old, larval Razorback Suckers have developed little more than digestive tracts, leading some biologists to dub them, "squiggles with eyes." Doesn't such scientific intellect speak just make your spine tingle and hairs stand up on the back of your neck ? Whatever. What they found was that the Colorado River canyon was almost completely bereft of mayflies, stoneflies, and caddisflies, river-edge specialists whose eggs are most likely to be exposed and desiccated by this hydropeaking. Tiny blackflies, which lay eggs in open water, are relatively unfazed by tides, but they don’t compensate fish for the loss of the more nourishing prey. Scarce food, more than perhaps any other factor (like larger predator fish), is what's holding native fishes back from increasing within their native habitat.
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.”
Biographic: In Search of Suckers

Photo: Michael Short, The Chronicle
Unfortunately other than giving honorable mention to floodplain shallows back prior to dam construction on the Colorado River and lack of shallows for pond insects and the zooplankton which would feed the little Razoeback Squiggles and other fish larvae, the Biographic article goes no further with it than that. Too bad because creating such artificial floodplain settings would probably go along way in making successful larval transition into larger juveniles and sub-adults. Like the farm/floodplain experiments which have proved quite successful in fattening up small Salmon fingerlings on zooplankton like that in the jar above right and later on aquatic insects who appear later. Below you can see the various forms of large aquatic insect life that help the California Salmon move up the food chain. The Grand Canyon Park Service quite often sings the praises with great enthusiasm about the canyon’s bizarre native fish, defending them against the complaints of the sport fish anglers who’d prefer to see the place given over to rainbow trout. And that's probably one of the biggest obstacles to recovery. The original intent of satisfying sport fishermen who were used to game fish from back east. Brian Healy, their lead fish biologist for Grand Canyon National Park, said this about the sport fisherman, “You always get that one guy who says, ‘Well, can you eat ‘em? No? Then what good are they?’” Such a typical response reveals ignorance of how an aquatic system actually works. If the average farmer has little understanding of how a natural ecosystem works in supplying plants with nutrients and in naturally maintaining checks and balances for keeping pests under control and trusts only what Industrial Ag Science tells him, then why should your average fisherman be any different ??? 😞

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And that is the other issue is humans having this need to see instant gratification in the way they view something's worth or value to them. In the Pacific Northwest and in California, it's much more easy to argue for conserving the Salmon, a fish that sustains the Native peoples and keeping the multi-million dollar commercial fisheries in profit. But here in the Southwest, it is considerably harder challenge to make the case for the humpback chub and razorback sucker, two species that support no industry, provide no tangible ecosystem services from the average person's perspective (which exposes their ignorance), and are effectively invisible to the overwhelming majority of park visitors. And yet this shouldn't be a surprise to anyone. The California river systems and other native fish there like the Delta Smelt, while not being a sport fish, do provide a further food source for larger sub-adult Salmon. And yet the idea of saving and preserving the Delta Smelt habitat is something controversial because of large scale industrial agricultural business interests and industrial water aqueduct construction interests.

Image - Ben Kiefer/UDWR
Take special note here of a native Colorado River fish called the Colorado Pikeminnow. This one in the photo on the right was caught by Logan Johnson who is holding a Colorado Pikeminnow on the Middle Green River in Whirlpool Canyon which is a tributary river north of the Colorado River. From the historical accounts and oldest photographs in existence regarding this fish, the one Logan here is holding is a juvenile by comparison to old photographs of fishermen holding six foot long Pikeminnows from their head to the ground. Such sizes no longer exist, but this really illustrates how such a western fish could have been a large game fish which is supported by the smaller less desirable sucker species we've been discussing. Again, all of this aquatic life starts with small tributaries and floodplains. 

Image - Tom Teske & Google Earth

Image - Tom Teske
The  image above is Tom Teske's of El Centro novice attempt to show the lake level near the beach. The view is toward Fish Creek Mts. But I believe he's done a very good job of illustrating the expansive shallows of the ancient Lake Cahuilla shoreline. This area would have been a prime spawning habitat area of shallow floodplains along ancient Lake Cahuilla's western shore. Incredibly, the Cahuilla Indians constructed numerous shallow fish traps, for which several bones of native Colorado River fish were present possibly by the millions. These fish traps above right are up near the city of Indio/Thermal in the southern Coachella Valley. In both traps and camps sites where the Cahuilla peoples lived, many of these fish bones have been found. I have no doubt that the larger Colorado Pikeminnow (formerly Colorado Squawfish) were in present in Lake Cahuilla in the deeper portions of the ancient lake, but the Humpback Chub and Razorback Sucker were smaller and apparently spawning along the shoreline. Clearly the Cahuilla Indians would have easily observed this shallow spawning behaviour. I've also seen this Razorback spawning habit in the sandy shallow shorelines of Lake Havasu along the California and Arizona border. So have others. Who hasn't as a kid figured out how to trap fish with cobblestone river rocks in a small stream and tried to catch them in a bucket ? We use to devise simplistic contraptions like that. The natives would have also made some type of special reed basket fishtrap for scouping up their prey like the one below I referenced from the Oakland Museum. 

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

Important References

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