Apr 1, 2020
In less than a minute, a large group of young salmon were released into the Sacramento River, en route to the Pacific Ocean.
These were no ordinary fish. Equipped with small transmitters, these baby salmon are part of a pilot project by the California Rice Commission and UC Davis. Grown in rice fields of Yolo County, scientists hope to find ways that the farm-raised fish will add to the dwindling wild salmon population.
This is part of a larger effort to reconnect the Sacramento Valley flood plains; strategically adding water to the landscape to benefit our environment.
“The flood plain is really core to the historical ecology of the Central Valley,” remarked Andrew Rypel, Associate Professor and Peter Moyle and California Trout Chair of Coldwater Fish at the Department of Wildlife, Fish and Conservation Biology at UC Davis. “Once upon a time, before people were over here, there was a lot of water up in the mountains. The snow would melt in the spring, it would come down and spread out across the central valley. The whole valley was once a huge flood plain. A huge wetland. Abundant Tule plants. Fish, Wildlife. That’s all gone now. But what we do have is we have a lot of rice field habitat, anywhere in the neighborhood of 500,000 acres. We need to figure out how we can use those habitats smartly, to help fish that have evolved using flood plain habitats historically to help boost the populations.”
“As many know, fish and farms have often been pitted against each other in California,” Rypel said. “It turns out that they might be able to help each other in the long run.”
If the research results are positive, it could eventually lead to many Sacramento Valley rice fields being used to grow salmon each winter.
“Ultimately we would like to develop what we would call a conservation practice standard,” said Paul Buttner, Environmental Affairs Manager of the California Rice Commission.
“We do this for bird habitat already, where we figure out what we want the growers to do to enhance their fields for habitat. Then we develop a practice that comes with a cost share payment for those that choose to participate.”
Jim Morris: This is an interesting spot for a field trip. I'm in Knights Landing. To my right is the Sacramento River and to my left are rice fields at River Garden Farms. And there's something unusual this year. There are enclosures raising juvenile salmon. This is year two of our pilot project. Hopefully, the results here will help California’s salmon population in the future.
Jim Morris: Welcome to Ingrained, the California Rice Podcast. I'm your host, Jim Morris. At the time of this recording, our world is struggling with COVID-19. My thoughts are with all and my hope is that something positive will come on this front very soon. We're following up on our previous episode, helping salmon. This is year two of the California Rice Commission's Pilot Salmon Project. And today is a big day as salmon raised on this farm are being readied for their journey to the ocean. I'm speaking with Andrew Rypel, who is associate professor and Peter Moyle and California Trout Chair of Coldwater Fish at the Department of Wildlife, Fish and Conservation Biology at UC Davis. So Andrew, it's kind of a big day today in this project. What's happening?
Andrew Rypel: We're seeing kind of a culmination of a lot of fieldwork that's happened over the winter here. We've been rearing baby salmon on rice fields for over a month now and they're now finally of size. We're putting transmitters in them and we're tracking them as they make their journey out to the ocean.
Jim Morris: And transmitters, I mean, technology has come a long way. So how accurate are they and how much can you learn from these transmitters?
Andrew Rypel: They're very accurate. So we're using acoustic transmitters, which means they transmit sound information. I wish we could use GPS tags like they do on turtles and wolves and things like that. But unfortunately, that signal doesn't penetrate water. So we have to use something called acoustic telemetry technology, that's we're putting in these, they're really the smallest available tags on the market and we're putting them in salmon as small as 72 millimeters in length. They transmit sound out into the river and we have an array of receivers deployed in the river, run by NOAA. And the detections are picked up on that array as they make their way out to the ocean.
Jim Morris: And how far of a journey is it in terms of length or time?
Andrew Rypel: Well, it's out to the Golden Gate and it usually takes them, well it depends on the water year, but anywhere between a few weeks to a couple of months. Usually, in years where it's wet and there's a lot of water in the river, they tend to hold and they don't go out as fast. In years that are a little bit dryer like this one, they tend to get out quicker.
Jim Morris: There is not a 100 percent survival rate at a farm or in the wild. And can you talk a little bit about that? There are a lot of challenges if you're a salmon in California.
Andrew Rypel: Yeah, that is the crux of the issue here. Survival of juvenile salmon. Out migration, survival into the ocean is low in California. It typically runs anywhere between three to six percent. So that's a lot of death on their way to the ocean. And it's a big reason why salmon populations are struggling in California. There's good information out there. For example, from the Columbia River that suggests that the smolt to adult return rate needs to be around two percent to have a good stable population. And we typically see smolt to adult return ratios in California below one percent. so the amount of survivorship that occurs during this critical part of salmon's life history can really make a difference in having a growing salmon population or a declining salmon population.
Andrew Rypel: So what we think is that by rearing salmon on managed floodplain habitat and that's what we're calling rice fields here, they can grow bigger, faster, get out in the river earlier and have increased survivorship that might increase that percentage up a good bit.
Jim Morris: Moving forward, there's a lot of effort to reconnect that floodplain. And can you explain what that means?
Andrew Rypel: The floodplain is really core to the historical ecology of the Central Valley. Once upon a time, before people were over here, there was a lot of water up in the mountains, the snow would melt in the spring. It would come down and spread out across the Central Valley. And really the whole valley was once a huge flood plain, a huge wetland, abundant Tule plants, fish, wildlife. That's all gone now. But what we do have is we have a lot of rice field habitat, anywhere in the neighborhood of 500,000 acres. So what we really needed to figure out is how we can use those habitats smartly to help fish that have evolved using floodplain habitats historically to help boost the populations. And I love the story because, as many know, fish and farms have often pitted against each other in California and it turns out they might actually be able to help each other in the long run.
Jim Morris: But the key for this aspect of it would be rice. Rice is a different crop than others and it works best for this application, is that correct?
Andrew Rypel: Rice is basically an agricultural floodplain. It's shallow, it's productive. We're just not using it for fish and wildlife the way we could yet.
Jim Morris: So once the tags are done and in and the fish are released, then there's a lot of monitoring. How long does all that take?
Andrew Rypel: Well, we'll know some information right away. There are telemetry receiver stations called real time stations that transmit data in real time right to your computer. And you get that just within a week, two weeks, as soon as the fish pass by those receivers. So we'll know some information right away. And then there are what are called autonomous receivers where researchers have to go out in boats, physically get the receivers, download the data from them, and that will take months towards the end of the summer. So we'll know some quick information that's really valuable right away, and then it'll take us a while to learn the whole picture.
Jim Morris: And does this speak to the value of the salmon runs? Because this is an incredible effort.
Andrew Rypel: I think it does. It is amazing how much research occurs around salmon on the West Coast and particularly in California. And the fact that... It's not just us, there are all sorts of researchers around the Central Valley that are doing salmon telemetry work. And I think that shows how important those survival rates are. We all want to understand why rates are low and what we can do to boost those rates up.
Jim Morris: And year one, a lot of storms, year two, not so much and it got warm, but such is life in California, are you still optimistic that there can be something of a success out of all this?
Andrew Rypel: I'm very optimistic. This year's work has gone quite well. We've been able to grow the fish like we wanted in the fields we wanted without them flooding and having problems. And what we've seen so far is that the salmon in at River Garden Farms here and then also at Knaggs Ranch, where we're also raising some fish, they've had incredible growth rates. Just like previous research has shown, they've grown super-fast and super-quick. So we're tagging fish right here today that are between 72 and 90 millimeters in length. And then we have a set of fish that we're keeping at the lab that we're going to study later on. Those fish are only measuring in the 50s. So we're talking about just tremendously higher rates of growth in rice field habitat and we're getting those fish out into the system faster and we think that's going to really help their survival.
Jim Morris: Paul Buttner is Environmental Affairs Manager for the California Rice Commission. And Paul, why would the Rice Commission work in this area?
Paul Buttner: We share the concern over the health of the salmon fishery here in the Sacramento Valley. Historically, these salmon used the floodplain for their rearing. Much of the floodplain is now agricultural fields including rice fields. So we're interested in seeing if we can develop techniques and strategies to essentially reconnect the floodplain by using winter flooded rice fields as salmon habitat.
Jim Morris: And assuming that there are good results from the project, how do you see this potentially playing out in terms of growers and helping salmon in the rice fields?
Paul Buttner: Well, ultimately we would like to develop what we would call a conservation practice standard. We do this for bird habitat already where we figure out what we want the growers to do to enhance their fields for habitat, and then we develop a practice and it comes with a cost share payment for those that would choose to participate.
Jim Morris: And partnerships are critical in getting this thing done. Can you comment about that?
Paul Buttner: Yes. This project would not be possible without funding from about a dozen organizations in total, including major contributions by the USDA’s Natural Resources Conservation Service, Syngenta, the SD Bechtel Foundation, Corteva, Grow West and others.
Jim Morris: I'm speaking with Rachelle Tallman, UC Davis graduate student who's been integral in this salmon project and last year's as well. And we are under the freeway near the Sacramento River, and what's happening tonight?
Rachelle Tallman: Yeah, so we're going to be releasing the fish that we raised at Knaggs Ranch and then a portion of the fish that we raised at River Garden, and we're just kind of timing it with dusk right now. So this is close to seven o'clock and we're going to be taking our Trek, backing it down the ramp and using a slide that we made for the fish to exit more passively than us handling them.
Jim Morris: And why at dusk?
Rachelle Tallman: We think that it's going to actually increase their chances of survival. In terms of predation, we want to minimize that. You know, when you're putting fish in tanks and getting them prepared to release, they're a little bit stressed out so we're trying to just buy them a little extra chance if we can.
Jim Morris: Of course there's still work to be done, but how do you feel? This is kind of a milestone in the project. How are you feeling?
Rachelle Tallman: Yeah, it's really exciting to release fish. It means like a portion of the project's done and completed. So I'm excited and I look forward to the second release that we'll do, which will be with more of our River Garden fish and our lab fish from UC Davis.
Jim Morris: With the salmon now on their way to the ocean, that will wrap up this episode. Thank you to all of our interview subjects. And remember, you can go to podcast.calrice.org to find out much more. And we would love to hear from you, so send us your comments and questions. Thanks for listening.