Archive for November, 2015

California has a weird dichotomy (ok, it has many weird dichotomies, but I am only going to focus on one right now), and that is most of the people who live in this state are in the southern half, but most of the water falls in the northern half. So, what are we to do? Since people need water to survive, there are really only two options. Option one, bring the people to the water. Option two, bring the water to the people. Obviously, we as a society, have chosen option two.

So there are a lot of people in the desert who are not going to move and who need water (remember this point). So be it, we can figure out a solution to this problem. California took a page from the Romans, and in 1963 began building an aqueduct to bring water from the northern half of the state to the southern half. Once it was completed, the series of canals, pipes, pumps and reservoirs stretched over 400 miles from Clifton Court Forebay in the California Delta near the city of Tracy to (at its farthest point) Castaic Lake in western Los Angeles County.

To collect all that water and then get it to move all that distance, including over some significant mountains, requires some significant pumps. These things are huge and take a huge amount of energy to run. They are so large that when turned on, they can alter the flows of rivers. When the pumps are off, the Sacramento and San Joaquin Rivers flow together in the delta and then pass through the Carquinez Straights into the bay and eventually into the Pacific Ocean. When the pumps are turned on, much of the flows of those rivers change course the are drawn to the pumps, and not out to the bay. This leads to a bunch of problems.

One is that with less fresh water flowing into the delta, salt water from the bay spreads farther inland. This can alter growing conditions for crops and water quality for many cities. The altered flows also affect many fish species. Chinook Salmon and Green Sturgeon and Delta Smelt and Steelhead are all species of fish that are protected by the California Endangered Species Act, the Federal Endangered Species Act, or both! Some species of these fish use water currents to guide their migrations out to sea and then back up the rivers. If the currents lead them to the sea and then back up to the rivers then everything works fine. However, if the currents lead them to the pumps everything is not fine. As I’m sure you might guess, fish that get pulled into those giant pumps do not survive.

Since they are listed species, we the people of California need to work to protect these fish so that they do not get killed off. Ok, we can figure out a solution to this problem. The California Department of Water Resources (DWR) has built fish screens to stop fish from being drawn into the pumps. However, what happens is that get pulled close to the pumps, and then just mill around right in front of the screen. What do we do with all these fish? They have to go somewhere, or else there will just be more and more and more of them which will not be good for the fish. Ok, we can figure this one out too. DWR built a system of pipes and tanks so that the fish could swim down the pipe and be collected in the tanks. Then the tanks are loaded onto trucks and driven away to the a release site in the delta. Before I move on, I should say that a lot of study, engineering, and biology has gone into the design of those pipes and tanks to insure that the fish are not injured as they move through them. However, this process has now led to more problems. Many predatory fish, many of them Stripped Bass, have figured out that lots of fish come out of those release sites. Underwater cameras have shown that the fish actually hear the trucks coming and gather at the base of the release pipe to eat the fish as they come down. So while we thought we were saving the fish from death by getting them away from the pumps, we were actually just sending them to their death down the mouths of predators. Well, we think we can figure out a solution to this problem as well by establishing more release sites and mixing up the schedule of when different release sites are used. This should make it so that the predators do not have established sites for a meal and so do not gather in such numbers which should mean that the fish DWR release actually survive and swim away. However, this strategy is still being developed and judging from the long list of problems so far, there is no guarantee that it will not lead to even more of them that we cannot yet foresee.

And remember, all of this is so that we can bring water to people living in the desert.

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As part of my current job with the California Department of Water Resources, I assist in collecting data for a study that is monitoring predators in the Clifton Court Forebay (CCF). The CCF is where water is collected and then pumped into the California Aqueduct for transport to southern California. One of the challenges to providing water to southern California is that there are several threatened or endangered species that live in the delta. Fish that get sucked into the pumps of the aqueduct do not survive, so keeping state and federally list species out of the system is important. The study I have been working on the past four months is examining threats to the listed species. One component of that study is to catch predatory fish such as Stripped Bass (Morone saxatilis), Largemouth Bass (Micropterus salmoides), and several species of Catfish (Ictalurus spp. or Ameiurus spp.). Once captured, these fish are tagged with little transmitters that send out signals that can be detected by underwater microphones, called hydrophones, that are setup throughout the area. By tracking when and where these predatory fish go, we hope to be able to figure out a way to reduce the number that come into CCF and eat the listed species.

Fall-run Chinook Salmon

Fall-run Chinook Salmon

One of the listed species we are concerned with are Chinook Salmon (Oncorhynchus tshawytscha), and I got an up close and personal look at one just a few days ago. As the team I was a part of was fishing in CCF, I got a hit on the lure I was using. It felt like a brick had been dropped on my line as the fish swam away from me and the boat. As I worked to real the fish in, everyone on the boat was getting curious to see what species I had hooked, just how big it was going to end up being. When I had finally pulled the fish to the surface, we were all really surprised to see that it was a Chinook! We are not supposed to catch salmon, and generally they do not attack the lures we use, additionally salmon at this time of year are not really eating but are instead focused on finding a mate and spawning. So this really was a surprise! When we got it on board to get the hook out of its mouth we quickly measured it (61 cm), weighted it (6.55 lbs), and got it back in the water so that it could go on its way.

Getting to see this fish, the largest fish I have ever caught, to hold it and then to watch it return to the water got me thinking a lot about Chinook Salmon. I am starting a new job on Monday which will focus on restoring many areas of the delta, and listed species will be a large part of those projects, so I figured that learning a bit more about salmon would be a good idea.

It turns out that there are four different runs of salmon that move through the California Delta. The different runs are defined according to when the different populations enter freshwater as they travel up from the Ocean and San Francisco Bay through the Delta and up the various rivers of California. The four runs are the Central Valley Fall-run, the Central Valley Late Fall-run, the Sacramento River Winter-run, and the Central Valley Spring-run. Each of these runs are considered to be evolutionarily significant units and so are monitored and managed for their specific needs.

Central Valley Fall-run Chinook, like the one I caught, are the most abundant of the four runs. They move through the area from July to December and spawn from early October through December. There is a fair bit of variability from stream to stream. Fall-run Chinook are an important economic factor due to the large numbers that are caught by both commercial and recreational fisheries in the ocean and by recreational anglers  once they reach freshwater. Even so, due to concerns about population size and the influence of hatchery-raised Chinook, this run is listed as a species of concern under the federal endangered species act.

Central Valley Late Fall-run Chinook migrate into the river systems from mid-October through December and spawn from January through mid-April. Again, due to concerns about population size and the influence of hatchery-raised Chinook, this run is listed as a species of concern under the federal endangered species act.

Sacramento River Winter-run Chinook pass through the Golden Gate from November through May and then move into the Sacramento River from December all the way through early August. They then swim up the mainstem of the Sacramento River to spawn from mid-April through August. These salmon used to go farther up the Sacramento River watershed and spawn in the McCloud River, the Pit River, and the Little Sacramento River. However, the construction of several dams have not blocked access to these historical spawning grounds. Despite these dams, the population of Sacramento River Winter-run Chinook was able to maintain a fairly healthy level until the 1970s when they began to decline. By the early 1990s only about 200 spawning salmon were observed. In 1989 this run was listed as endangered under the California Endangered Species Act and they were then listed as endangered under the federal Endangered Species Act in 1994.

Central Valley Spring-run Chinook begin moving up the Sacramento River from March through September. They generally the find areas of cold water to wait out the summer and then spawn from mid-August through October. This run used to be the largest in central California however, only small remnant populations are left in small creeks that make up some of the tributaries of the Sacramento River. Some Spring-run Chinook still occur in the mainstem of the Sacramento and Feather Rivers, but they sometimes hybridize with Fall-run Chinook. The reduced spawning areas, small population size, and hybridization threat lead the Central Valley Spring-run Chinook to be listed as threatened under both the federal and California Endangered Species Acts in 1999.

So, there you have them, the four Chinook Salmon runs of the California Delta. There are many other runs in other parts of the state, all with their own unique stories and histories. It will be interesting to see how I will be interacting with these runs in the habitat restoration work I will be doing. I will keep you informed!

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