Dr. Peter Moyle lays out a six-point plan for helping salmon adapt to California’s warm future
We don’t have to accept a future without salmon, but we need to take action now, says Dr. Peter Moyle, Associate Director at the UC Davis Center for Watershed Sciences. He laid out the six steps that the state can take to increase the resiliency and viability of salmon in the face of California’s changing climate at the California Salmon and Climate Variability Symposium held earlier this fall.
Dr. Peter Moyle began by presenting a diagram of the life cycle of the coho salmon, reminding of the marine-freshwater connections between salmon and the marine environment. “There are all these different cycles, and what happens with freshwater affects what happens in the marine environment and vice versa,” he said. He acknowledged the complexity of the diagram, noting it’s one he bases an entire lecture on in his class, so he next explained in simple terms it means.
“Basically when ocean conditions are good and freshwater conditions are good, salmon populations tend to be large, and so the limiting factors of main importance become competition, predation, habitat, biological factors,” he said. “However when freshwater conditions are poor even when marine conditions are good, the salmon populations can still be fairly large; the main control on the numbers seems to be freshwater habitat. Likewise, when ocean conditions are poor and freshwater conditions are good, it becomes the food in the ocean that becomes the limiting factor. When both are poor, food and space are both limiting, and the fish can get into an extinction spiral, and this increasingly what we observe is happening.”
“What’s going on in California today is that we almost never have good conditions in freshwater for salmon, unless you count hatcheries,” Dr. Moyle said. “There are 32 species of salmonids in California, 44% of them are already listed and another 25% qualify for listing.”
“If you look just at the anadromous forms, the 21 species of distinct taxonomic groups of salmon and steelhead in California, half of them are already listed, and another quarter of them really qualify for listing, so we clearly are not doing a great job of managing salmonids in California.”
Dr. Moyle pointed out that this includes both coho salmon ESUs. “Coho salmon are one of the species that seem to be on their way out in California. It’s very hard to be optimistic about their future.”
California has a history of highly variable climate as reflected in our present drought, he said. “You can argue that is partly driven by climate change, but in fact our drought is part of a natural sequence of events that has been historically part of California’s long term heritage, and the result is in recent years, reservoir levels have fallen with less cold water supply available for fish. We are experiencing record heat as well.”
He presented a graph from a study he did with PPIC showing the percentage of stream gages with flows in the lowest 10% of historic conditions. “About half of all of our stream gauges are recording record low flows in streams,” he said. “I know from my own surveys going on in California streams that a lot of streams are dried up, so this is clearly indicative of really poor natural conditions exacerbated by all the things we do on the landscape.”
“The biggest issue is all the things that we are doing in the environment with all the competition we have for water in this state,” Dr. Moyle said. “Basically we’re competing with fish for water and we’re winning.”
A study done by Ted Grantham, one of Dr. Moyle’s post docs, found over 1400 large dams in the state that significantly affect water. “There are 753 dams that are potentially harming fish, and 250 of these are more than 20 meters high, so this is obviously a big deal on the landscape,” he said. “Over 70% of the habitat, especially our cold water habitat, is above these dams and the habitat below them is highly regulated by the dams so we really don’t have any pristine habitat left for salmon and steelhead. Dams are just one factor, but there are a lot of things working against the survival of salmon in California in their freshwater environment.”
A paper came out recently which said most experts have concluded that by 2100, wild salmon in the Central Valley will be extirpated or minimally abundant if current trends continue, and a similar statement could be made for salmon on the coast as well, Dr. Moyle said.
“Bob Lackey has written this as part of a book that he edited on the future of wild Pacific salmon saying generally California’s a lost cause, so it’s up to us whether we accept this or not,” he said. “Clearly, if you look at the trends in salmon populations, even the non-migratory populations, this seems to be the attitude we have because things are declining pretty rapidly.”
So the big question becomes what can we do? “There is a lot we can do,” assured Dr. Moyle. “We don’t have to accept the idea that salmon are going to disappear from California just because the trends are looking in that direction right now.”
An action plan for salmon
He then gave his ideas on actions that can be taken to help salmon adapt to changing conditions:
1. Adopt a statewide strategy for aquatic conservation.
“There are a lot of strategies out there, but I don’t see anything that’s really called truly systematic statewide strategy that would involve protecting examples of all major habitats and freshwater, having plans for maintaining self sustaining populations so all native species, more than just salmon, and also have drought protection,” Dr. Moyle said. “We’re all in panic because we’re in the fourth year of drought, but nobody seems to have thought about what if we have two more years of drought. Right now, El Nino is coming to the rescue, right? But what if we didn’t have that El Nino. The next time we have a drought, it could be a six or ten year drought and we are not ready for it.”
2. Protect the best of what’s left.
Dr. Moyle said that one of his particular favorite areas is a project he has been working on with Western Rivers Conservancy Blue Creek up in the Klamath Basin. “This is a great example of the way we should be doing things,” he said. “It’s a cold water stream and it provides a cold water pool in the mainstem Klamath River which is a major resting place for adult salmon migrating upstream. Essentially the Western Rivers Conservancy is acquiring the entire watershed on behalf of the Yurok tribe, and the Yurok have promised to make this into a Yurok tribal salmon sanctuary and to manage it in perpetuity. They see ways they can support the tribe by doing this. This is the kind of forward thinking we need. Again, we’re talking about entire watersheds being protected. You could argue this is exceptional, but we need more of these exceptional things.”
3. Protect spring-fed streams in the state and manage them for salmon.
Spring-fed streams are important because they have the combination of being both cold and being of high productivity, Dr. Moyle said. “Work in his lab has shown that spring-fed streams produce a lot more bugs than runoff streams, because runoff streams are highly variable whereas spring-fed streams are fairly constant.”
This shows you the Shasta River as it pretty much looks today, it’s an amazing place. This is not the way it looked a few years ago. ”Places like the Shasta River are just absolutely extraordinary when you get into those springs and look at the productivity which can be translated very readily into fish,” he said.
Other studies have shown how coho salmon exhibit compensatory mechanisms in a spring-fed river, so when temperatures get high and water warms up as they go further downstream, the salmon growth rates actually increase. “Because there’s so much food, they can compensate for the higher temperatures, which should be stressful, by eating more,” Dr. Moyle said. “This is a reason to be optimistic because it tells you that if we manage our streams right, fish can adjust to the conditions that we provide them, provided we know what they need and provide everything they need.”
Another success story is Big Springs Creek in the Shasta Valley, a tributary to the Shasta River. Cows used to graze in the stream in the winter because the stream was warmer than the air. The Nature Conservancy acquired the Big Springs Ranch in 2009 and fenced off the stream from the cattle, almost immediately, there was restoration of colder water, channels redeveloped and the vegetation came back, and the insects came back. “Again there are success stories out there of things we can do to improve the situation for salmon,” he said.
4. Restore and reconnect floodplains.
There are a lot of studies and work going on the rivers in the Central Valley to reconnect floodplains and make salmon habitat out of these floodplains. He presented a slide showing two salmon, the smaller one on top coming from the Sacramento River, and the fatter one on the bottom coming from a floodplain. “Salmon can thrive in rice fields,” he said. “It’s really a nice example of how you can grow rice in the summer and probably grow salmon and ducks and all kinds of other things in the winter,” he said. “That’s the kind of thing we can really work towards, and part of the idea of floodplain restoration in the Yolo Bypass is that there’s lots of things you can do to make it into a really functional floodplain for fish.”
5. Improve environmental flows below dams.
“Environmental water seems to be the first thing sacrificed during these droughts as we found out,” Dr. Moyle said. “We do have legal tools for dam reoperation. There’s Section 5937 of the Fish and Game code, and this whole study that Ted Grantham and I did was based on the idea on how do you identify the dams to which you could apply this section of the Fish and Game code to that would improve flows for fish below dams. I always like to point out that the wording of Section 5937 of the Fish and Game code says ‘the owner of a dam must keep fish in good condition below the dam’. It does not say except in times of drought, and that’s pretty much the way we treat these areas now.”
6. Reconcile ecosystems
Lower Putah Creek is a 30 kilometer stretch of riparian habitat that is regulated by dams. Dr. Moyle showed a picture of the creek in February of 2014 after having no rain for a year, and pointed out that the bank was dry but the creek was doing well. “The riparian vegetation, the birds, the trees, and everything in this creek is really doing well in the drought, and that’s because there are guaranteed flows down the stream as releases from Monticello Dam.”
Putah Creek is just a shred of habitat surrounded by ag land in Yolo County. “What we have is a novel ecosystem,” he said. “This is an ecosystem that is managed in part for native fishes and native birds, but in fact about half the flora and fauna is non-native, so it’s a system that’s highly modified. It’s deeply incised in the landscape. We’ve never seen an ecosystem like this before in terms of it’s composition of the way it exists, and we have to be thinking in those terms. We have a new ecosystem, how do we manage it? This is where it becomes a model for reconciled aquatic habitat and riparian ecosystems.”
“This is now a major habitat for native fishes,” he said. “The lawsuit resulted in a flow regime that was designed specifically for native fish; it took a relatively small part of total annual yield of the project, so it was viewed as quite reasonable by the courts. Basically once the new flow regime was in place, the fauna of the stream where there were fish switched from being alien species to being native species primarily. The aliens are still there, but they are a minor part of the fauna. And we have permanent flows now whereas before we had intermittent flows in much of the lower creek. This did not have a high water cost associated with it; it’s done by smart management of the water.“
Salmon are back, too. Dr. Moyle said about 200 fish came up last year. “This is also an example of how salmon can adapt to new systems,” he said. “These fish are primarily coming up in late November and December. They seem to be fall run Chinook, there are a bunch of hatchery fish in there, but they are coming up and they are spawning successfully and the young are moving out of the stream.”
In conclusion …
Dr. Moyle then wrapped it up by talking about reconciliation ecology as a basic approach to conservation. “This is the idea that humans do dominate all ecosystems, especially in California,” he said “There’s no such thing as a pristine ecosystem in this state, so most of these ecosystems are novel ecosystems with alien species living in altered habitats. Drought and climate change just increase the need for this kind of approach, so to really approach this idea that we’re in charge, let’s figure out how we want these systems to work and let’s figure out what we want to have around in the future. Whatever we have, they are going to be ecosystems that do not necessarily resemble what the historic ecosystems that were there, but we do want to maintain these systems to keep around the things we want.”
“I hope salmon will be one of those things that we’ll be able to maintain for the future,” Dr. Moyle said. “We can do it, but we just have to be willing to make the sacrifices to do so.”
“So with that … “
More from the California Salmon and Climate Variability Symposium on Maven’s Notebook …
- Gimme Shelter: How habitat restoration can help improve salmon resiliency to climate change (Dr. Ted Sommer)
- A regional-scale view of climate impacts on California’s salmon habitats (Dr. Nathan Mantua)
- Juvenile Chinook challenges in the Central Valley: baked, boiled or bass turds? (Dr. Sean Hayes)
- Conserving Chinook salmon at the southern end of their range: Challenges and opportunities (Dr. Rachel Johnson)
For more from the symposium …
Coverage of Maven’s Notebook has focused on the freshwater science presented there, but it’s only a portion of what was covered at the symposium. Many more topics were presented, including a panel discussion with agency officials and stakeholder. I encourage you to explore the rest of the symposium at the link below.
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