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ALICIA HAMANN:

Welcome to the EcoNews Report. I'm Alicia Hamann, your host this week, and I am joined by a wide variety of fish experts to talk about an exciting project on the South Fork Eel. I'm also joined by my colleague Tom Wheeler, the executive director of EPIC.

TOM WHEELER:

Hey, Alicia. Thanks for having me.

HAMANN:

Hey Tom! And we are joined by Marisa McGrew from the Wiyot Tribe's Natural Resources Department.

MARISA MCGREW:

Hello everyone.

HAMANN:

Philip Georgakakos, research scientist at UC Berkeley.

PHILIP GEORGAKAKOS:

Thanks for having me on.

HAMANN:

Yeah. And Gabe Rossi, who is also a research scientist at UC Berkeley.

GABE ROSSI:

Good morning.

HAMANN:

Good morning. So today we're talking about this really exciting project, and I know there are actually other partners who aren't represented here today, but does one of you want to just give us a rundown of this massive installation in the South Fork of the Eel River and what its purpose is?

GEORGAKAKOS:

Gabe, do you want to lead us off?

ROSSI:

Sure, happy to do that. Yeah, yeah. So the project, it's hard to start talking about without talking about everything that's connected to. But the project in very short is to build a weir, which is a floating fence in the upper South Fork of the Eel River. And the objective of that weir is to prevent the migration of this invasive fish that is in the eel, which is known as the Sacramento pikeminnow. And so this floating fence is intended to prevent these animals from migrating up into the headwaters of the river where they have some negative interactions with our native species. And also to try to remove pikeminnow as many as we can from the river. And also just to learn more about the movement and life history of our native animals too.

HAMANN:

Neat. And so are other fish able to pass through the fence? How does it work with the native species?

ROSSI:

Yeah, absolutely. So a weir, as I said, it's a floating fence and weir technology is ancient. Been around for thousands of years. Indigenous people around the world have used weirs. And so what we're using is a modern version of ancient technology. It's built out of PVC pickets that are connected on stringers. And you can space the pickets appropriately so that different animals are able to pass through or different animals are not able to pass through. And so we designed this weir so all of our juvenile salmonids and smaller native fish can swim right through it. And then larger animals have to go through our trap box where we can either remove them if they're an invasive animal or we can send them on their way if they're a native fish.

HAMANN:

And I guess we should probably talk about who all is involved in making this project happen. We've got two of you here from UC Berkeley and we've got one of you here from the Wiyot tribe. Who else is a part of this project?

ROSSI:

This is a big, really big collaborative effort, so I'm glad you mentioned that. And, you know, I work for UC Berkeley. I'm also the UC Berkeley CalTrout freshwater ecologist for our coastal rivers. So I work with the non-profit CalTrout, who is the grantee here actually for this project. So they're a really important part of this effort. Also, CDFW and NOAA Fisheries have been involved in this from the beginning through multiple technical advisory committees, and then a number of local consulting firms, still water sciences, involved in this effort. And they were working with the Weyatt tribe on a very, an earlier version of an invasive species management plan for pikeminnow. And really this builds off of a lot of history, I think, of managing this fish and people working together to try to understand the best tools and approaches to manage this fish. That happened before Phil and I were involved as well, you know, years before probably any of us were involved. So we're kind of building off a history of people working towards trying to come up with the best solutions for how to manage pikeminnow in the Eel.

GEORGAKAKOS:

Alicia, I'll also add that the Bureau of Land Management is also involved. Zane Ruddy is one of our partners too, so it really is a pretty big collaborative group.

WHEELER:

All right, I am kind of a newbie when it comes to fish stuff. Alicia's one of the friends I always turn to for information on this. So forgive the dumb question, and maybe Marisa, I can grab you into this conversation. What are pikeminnow and why do they suck so much?

MCGREW:

Glad you asked. I do want to say that pikeminnow are a beautiful fish. They have their place in the world and they are native elsewhere, very nearby. They're native to the Sacramento River and the Russian River. But yeah, they are not native to the Eel River. And I mean, I would almost give this over to Phil because Phil studied pikeminnow in his PhD work, I want to say. Yeah, I, yeah, they're a beautiful fish. And yeah, I think Phil can speak more about their ecology.

WHEELER:

There.

GEORGAKAKOS:

Well yeah I'll just second Marisa and say it's not worth like demonizing the pikeminnow they they were introduced. By humans in the eel in the late seventies. And have really spread throughout the whole basin since their introduction into Lake Pillsbury. And they negatively impact our- our native fishes in a number of different ways but a few are. One they get really big. Like up to three inches long. And they're dangerous at some point when they're that large. They also can compete with our native fishes for the same prey. So like size matched pikeminnow and say a steelhead will both be consuming. Invertebrates and pikeminnow will eat a portion of those invertebrates and remove that available prey. For a steelhead. And the other thing that they do is they just scare all the native fishes. So when a big pikeminnow occupies a pool. They'll make different shallow riffles. And they won't use that pool habitat which can be really valuable for a number of different reasons like. To forage or- the pools actually have some temperature refugia to so so there's like a number of different ways the pikeminnow. Are negatively affected. The tide is kind of pretty deeplicher water rate

HAMANN:

And so speaking of temperature, my understanding is that infrastructure like the dams that tends to warm the waters a bit more actually makes for a much more inviting habitat for pikeminnow because they prefer slightly warmer waters than some of our native salmonids. Is that accurate? Can any of you speak to the different kinds of habitat preferences that salmonids and pikeminnow have?

GEORGAKAKOS:

There is some overlap in the habitat use between pikeminnow and salmonids. A pretty interesting study by by Brett Harvey showed that. pikeminnow do compete with steelhead and they're much more effective competitors under warmer conditions. So when waters are warmer they have more of a negative impact which. Is kind of along the lines of what you're asking. And the pikeminnow are also distributed along the whole river so in the lower reaches there's less overlap in the headwater reaches. So they're more active in the headwater reaches. But our migratory fish do have to travel through those habitats as they go to the ocean. So there's more overlap in the headwater reaches but they still encounter the migratory salmonids still

ROSSI:

I think that's a really important component to all this is the is the mainstem use of pikeminnow. I mean, there certainly are tributaries, especially tributaries with low gradient confluences that pikeminnow migrate into, but they're predominantly distributed through the mainstem and all of our anadromous fish. Anadromous means you go to the ocean, right? So these are salmon that are born often in tributary streams that have to migrate out of those streams, traverse the mainstem and go down to the ocean. And in the world of salmon recovery, we've been spending millions of dollars trying to recover our tributary streams to get them so that they're productive for spawning and rearing again. But all that money that we're investing in that recovery for it to be successful, these animals have to survive in the mainstem, have to grow in the mainstem and have to make it to the ocean. And so the presence of pikeminnow, as Phil said, not only through predation, but through altering the way they use mainstem habitat is potentially really problematic for that recovery. For that recovery.

HAMANN:

Yeah, and how do we know what kind of habitat pikeminnow use? Is there anyone, Marisa, has the tribe, I think, maybe done some work monitoring pikeminnow and understanding the way that they use the watershed?

MCGREW:

Yeah, so the tribe has been doing snorkel surveys and Phil has been doing those snorkel surveys also a little higher up in the South Fork. So we've been observing them mostly, kind of, almost everywhere that salmonids are. Yeah, in deep pools and shallow pools, even at like the tailouts of riffles. And yeah, the tribe has been doing snorkel surveys for them for a couple years now and still doing those currently.

HAMANN:

So let's go back to the weir. I was really fortunate to encounter several of you just after it had been set up. There was a lot of excitement. Can, can you guys walk me through the process of what it was like to put this infrastructure into the river? Were you all camping down there? What, what's that involve? Are there, what are the complexities of pulling something like this together? Marisa.

GEORGAKAKOS:

You want to talk a little bit about it?

MCGREW:

Yeah, it was, yeah, I mean, the process itself was a huge team effort. Yeah, I mean, us three here were there along with other folks from the natural resources department at the tribe and also plenty of folks from CDFW and Stillwater and also, yeah, just like many community members where the weir is, like have been an extreme help in just like providing like access to where the weir is and also providing a place for technicians to sleep where the weir is. And yeah, it has been an amazingly collaborative project. But yeah, more logistics wise, we installed it, oh my gosh, mid April. Yeah, like right at the height of the SRF conference. So it was just horrible timing. It was great timing. But yeah, just like, yeah, a lot of people were busy. But yeah, just like the amazing collaboration and like teamwork of everyone like coming together to install it. And also Kramer Fish Sciences who designed the weir and like they came out and helped install it. And yeah, also folks from Cal Poly Humboldt as well.

ROSSI:

Yeah, we definitely need a shout out Kramer. That was, I was waiting to get that opportunity. They, they've been an amazing partner. They're experts in these resistance board weirs, which are a specific kind of weir. And they've been building them all over the world, Norway and in Alaska and all over California. And so they're very, they're really experts in it. And Jesse Anderson and Joe Murs came out and, and really directed traffic. We were the, we were the labor and they were the designers. And so it was really good having the folks who have expertise in this technology to help us with the installation. It's a lot of heavy lifting. You're moving weir panels under the river. We had to drive some, some big rebar to attach what's called a substrate rail, which is a piece of iron that holds the whole weir in place. That's the only thing that's actually attached to the bed. Everything else is floating. And so what's nice about this structure is you can remove it and it would be as if it was never there. There's no concrete. You don't need a tractor. It's all done by hand, but it is a significant manual labor over three days of, I think it was 90 plus pieces of rebar that went into the riverbed. A lot of heavy pieces of metal in the substrate rail. And then these weir panels are 20 feet long and they're, they're bendy and difficult to handle. And so hooking them up onto the cable that's connected to that substrate rail was, was, yeah, was a continuous, a significant effort. And I really appreciate a big team of young, strong, healthy individuals who were there to help us make this happen.

GEORGAKAKOS:

Lots of sandbags, too.

ROSSI:

Lots of sandbags, yeah.

HAMANN:

Gotta love those sandbags. So you mentioned that the Weir isn't a permanent structure. What are its long-term plans? Is it going to come out in the wintertime? Is this going to be something that stays in for years? What does the future look like?

ROSSI:

like? Well, I just, I would say that I think an important thing to note here is this is an experiment. And Phil has a great anecdote I want to want him to give a little bit about a paper written in 1950. But this, this, which actually recommended using a weir for managing pikeminnow. So 70 years later, here we are. But this is an experiment to see if we can actually manage the fish this way. We know there are some pikeminnow that are not migratory. So they're above the weir, but we're in a really good position given the monitoring that's already gone on for the last eight plus years, looking at pikeminnow populations, both with the Weeot tribe, with the Eel River Recovery Group led by Pat Higgins, and then with Phil's work to actually be able to say whether we're having an effect here. And so we're hoping that if we see that this is a beneficial and also that we're have high confidence that we're not negatively affecting our native fish, that this is something we can do again in subsequent years until we really start to see the benefits to native fish that we're hoping to incur from this work. But we're also willing to pull the plug if it's not, if A, it's not effective or B, it's not, it's harming our native fish. So we were taking this really carefully with regards to protecting the native animals, protecting the ecosystem in a way that where the risk is not worth the reward here.

GEORGAKAKOS:

I'll just follow up with that quick anecdote from Taft and Murphy from a paper published in 1950. And it says, the migratory behavior of the squawfish has led to the suggestion that their numbers in a stream could be reduced by constructing a barrier to upstream migration, a barrier that would stop the pikeminnow but allow migrating trout and steelhead to pass. So definitely not a new idea. And here, like Gabe said, 70 years later, we're doing this experiment. And one of the unique things is that we have all these snorkel surveys to try to assess whether we're effective or not.

WHEELER:

The Econews report and we're talking about fish weirs in the Eel River to trap pikeminnow. So I'm curious about long-term efforts regarding pikeminnow in the Eel River. Is there talk about complete eradication efforts? Are we now in a world where we are attempting to have both species coexist within the Eel River?

ROSSI:

That's a great question. I don't know that there is consensus on whether or not we feel like we can completely eradicate this animal at this point, at least not without taking such extreme measures that we're going to harm native fish in an unacceptable way. I think more likely is that what we're trying to do is to reduce the number of large, really piscivorous animals that are having a big impact. So piscivorous mean fish eating pikeminnow that are having a big impact on our native fish and allow the native fish population to recover in addition to all the other recovery work that's going on with salmon. Obviously, pikeminnow is not the only thing inhibiting salmon recovery or other native fish recovery in the eel. We know there's a host of other issues that are being worked on. But the hope here I think is that as those salmon populations recover in response to all this work, we hope that they kind of reach a point where impacts from pikeminnow and adaptation between these two animals occur and the recovery of fish can continue. I think pikeminnow management may be a long-term necessity in the eel. We could be talking about decades, but that may be what it takes as we kind of nurse these fish back from the litany of insults that they've endured at our hands. So that's the goal.

GEORGAKAKOS:

I'll add that there are some interesting approaches that are potentially on the horizon. One of them is called the Trojan Y, which some folks at Cal Poly Humboldt are using, where you modify a fish genetically to make them have more male offspring. And eventually, as they reproduce, you swamp a population with males and you have less offspring in the long run. So that's something that's being investigated. But I also wanted to pass over to Marisa because the weir is like one tool in our eradication toolbox and the Weotribe and Stillwater Sciences have really been pioneering a whole bunch of different approaches and seeing what's successful to do in conjunction with the weir to try to remove fish.

MCGREW:

Yeah, so we've been doing a whole host of suppression methods that include boat electrofishing, gill netting, active gill netting, let me clarify, and also spearfishing. And there's pros and cons to both to all these methods. Also seining forgot to mention. But yeah, pros and cons to each method like spearfishing requires like a lot of skill. It also like took a while to like get that permitted to spearfishing in the eel. And yeah, it requires a lot of skill. It requires this expensive equipment as well, which I want to thank Bill Matsubu for letting us borrow his spearfishing equipment. He was the previous fisheries biologist at the Wiyot tribe. And yeah, but spearfishing does like help like single target those fish. And yeah, our gill net method is also really good and good in like getting the more adult gravid females that are the really the critical fish to get. And yeah, our boat electrofishing method is also really successful in like acquiring like large numbers of fish. But then there's the whole problem of where can we bring a boat into the South Fork? Yeah, access is sometimes that's not going to happen for a boat. Yeah, so the tribe and Stillwater have been really like doing these suppression methods for a couple years now. And we'll, yeah, as Gabe said, it'll be a continued effort to put some control on this population of fish.

WHEELER:

Alicia, I know Friends of the Eel River has been hard at work to forward Eel River dam removal and I imagine that there's a connection between the dams on the Eel River and Pikemanoe. Can you talk about how the dams might negatively impact salmon and positively impact pikemanoe?

HAMANN:

Yeah, yeah. Well, so as Phil mentioned before, pikeminnow were actually introduced in Lake Pillsbury Reservoir. My recollection of the story is that there were some fishermen who were using pikeminnow as bait fish, and when they were done for the day, they just chucked their leftovers overboard. And boy, there apparently were some males and females in there together that made babies. And now look at the mess we're in. So PG&E actually is supposed to do pikeminnow removal and work on eradication efforts. I can't really speak to how successful that's been except a point to all the pikeminnow in the watershed. But the reservoir also creates really ideal conditions for the pikeminnow. We talked before about the thermal tolerance for pikeminnow versus steelhead and salmon. And one thing that's been really interesting recently, just starting last year, PG&E is making a much more solid effort at maintaining cold water diversions out of Scott Dam. They're keeping a larger pool of water behind the reservoir to ensure that temperatures stay cool and remain at the place where steelhead and salmon can continue to be competitive with pikeminnow. Once you start to get above a certain temperature, the salmon would start to get more lethargic and have a more difficult time. And the pikeminnow continue to thrive at some of those temperatures. And then three, and this is something that I just think is the wonderful opportunity of dam removal. Once we can get salmon and especially steelhead into that upper basin habitat that's trapped behind Scott Dam, there's real hope that it will serve as a refugia from pikeminnow. Not only is it very cold water that in fact stays cold during the hot, dry summers, but steelhead are these really incredible athletes. And so if we can allow steelhead to access some of that habitat, there's going to be safe rearing habitat for their juveniles. And yes, they will still have to, as Gabe described earlier, traverse the pikeminnow superhighway that is the main stem, but it'll be a safe place for them to grow and strengthen a little bit. Yeah, it's just, there's a lot of reason to be hopeful that dam removal is going to make a big impact on giving salmonids the chance to really stand their ground against the pikeminnow.

ROSSI:

I think a point to add to that, too, is the value of what we call life history diversity. There's a concept in ecology called the portfolio effect. If you've ever invested in the stock market, you probably heard of the portfolio effect, right? You buy some low-risk stock, you buy some high-risk stock, and then no matter what the market does, you've got some return on your investment. Well, that idea came right out of nature. Mother nature does that, right? And so a population of salmonids has a lot of different ways they live their lives. And some animals might migrate early, some might migrate later, some might migrate at a larger size, some at a smaller size. And with respect to risk from predation of pikeminnow, it's a big benefit to recover that life history diversity in our native fish so that they're moving at multiple different times throughout the main stem, at multiple different sizes and physiologies, which makes them less likely to be impacted by predation. And removing those dams will, amongst other things, improve the opportunity for that expression of life history diversity, just like you said. So that's a really important goal in salmon recovery, not just because of pikeminnow, but of course the potential reduction of risk from pikeminnow through life history diversity is a big goal for us as well.

HAMANN:

Yeah, and I think we're all well aware of what climate change is doing to our world and preserving that life history diversity is a really great way to give species the resilience, or not to give them the resilience, because they've always had that resilience, but to allow them to continue having that resilience that we've narrowed down a bit. Absolutely. So we talked a little bit about how this project is somewhat of an experiment. When will we know if it's been successful? You know, is there a point at which you're all going to stop and look at the figures and say, okay, this is working or this isn't working? What does that timeline look like?

GEORGAKAKOS:

So we've got a couple of different ways that we're evaluating the success of the weir. The first, which we've already talked about, is these snorkel surveys that are occurring both above and below the weir, which we have done in years past already. So we're going to swim about 65 kilometers of river this year, and then we'll compare the counts of pikeminnow that we get on this year's dives to previous years, and our hope is that they'll be lower. So that's one way that we'll evaluate the success, is just by counting pikeminnow above and below the weir. Another one that is pretty interesting is that we're, with collaborators, doing an acoustic telemetry project, and what we've done there is we've caught and tagged a bunch of juvenile salmonids, and we have these receivers that we've placed throughout the south fork of the eel, all the way down to near Fortuna, actually, and when our tagged fish swim past these receivers, they can detect them, and we know something about their travel times between those different locations, and also we can, with the help of statistics, try to calculate how many are perishing, so we can estimate survival at different reaches of the river, too. So if we see higher survival above the weir than below the weir, that's one indication that, another metric to evaluate the success of the project. But all of that will be compiled towards the end of the summer, so over the next couple of weeks, Marisa and I and Gabe are going to be out doing these dives, and once we do that, we'll have counts. The acoustic telemetry project takes a little bit more post-processing. It's super data-heavy, so those results will probably be a little bit slower.

ROSSI:

Maybe a little PSA on that is if you're diving, if you're having a good time on the Eel River in our South Fork and you see some steel cable attached to a white PVC tube with some housing on it, please leave that in place because those are our acoustic receivers that we have that are listening for tagged fish moving through. And so we've had some well-intentioned people thinking those were nefarious objects in the river pull them out, which I appreciate the spirit of that. So we put some signage on those and hopefully they stay in place.

WHEELER:

So are y'all eating a lot of pikeminnow these days? And if so, do you have recipes for how to best prepare pikeminnow? This is going to be a long video so I ask much of you to Derp this day!

MCGREW:

been such a goal of mine and I think also Phil and Gabe's. I don't think any of us have correct me if I'm wrong you two but I will put a plug in for so other tribes do eat pikeminnow like where where they're native to so they are edible. We don't know how to prepare them. I think there's just gonna be maybe some experimenting on our own time to yeah, try to eat them.

HAMANN:

I mean, it's good if you fry it, right?

GEORGAKAKOS:

I've got some high hopes for fish cakes.

ROSSI:

Yeah, exactly. Fish case. Old timers we've talked to have not given us glowing reports of pikeminnow taste, but we have about 150 in the freezer right now. So we'll definitely have some opportunity to try out different recipes. Any culinary interests working with invasive species at Cal Poly Humboldt hit us up. I wanted to point to Marisa's point about the other tribes. There's a really interesting tribal connection here too. Marisa, you want to talk a little more about the Robinson Rancheria maybe? Yeah.

MCGREW:

So the Robinson Rancheria, which is down near Clear Lake, they, there was pikeminnow in Clear Lake, but they are no longer present. They have been totally extirpated from the lake. So I think it was, it was Bill, previous fish biologist here at Wiyot Tribe, made a connection with a tribal member and employee through Robinson Rancheria at a conference that we all attended. And yeah, they are very much interested in maybe acquiring some pikeminnow to, and this is like a whole other thing of how to possibly like transport live fish and reintroduce them back into Clear Lake. But yeah, that is a connection that we've made and hopefully trying to figure out how to make that happen. Yeah, reintroducing them into the lake, as well as yeah, maybe passing off the dead fish that we have for consumption.

ROSSI:

Yeah, it's fascinating to me how the mishandling of the same animal has affected indigenous people in totally different ways. Right, I mean, our weir is on Wailaki territory. Obviously, the Eel River tribes who have been negatively impacted, as well as the rest of our community who love this river, are impacted because of the introduction of this fish. And then just nearby, you have a whole other group of people who have been impacted because of the removal of this fish, which was impacted because of the introduction of an invasive bass. So, it's a lot of historic mishandling we're trying to undo as much as possible.

HAMANN:

Yeah, these ecosystems are both delicate and resilient. Well, I understand that one of you may have an excellent fish joke for us, which I would just love to hear. I can always add more jokes to my repertoire.

MCGREW:

Okay, what is the difference between a fish and a guitar? You can tune a fish, but you can't tune a guitar. Oh.

HAMANN:

Oh boy.

ROSSI:

My seven-year-old's gonna love that one.

HAMANN:

Yes, thank you very much. I think you were the one who was showing me some cool aerial photos of the weir. Could you email those to me and we'll include them in the show notes and use them to promote the show?

ROSSI:

Yeah, in fact, Caltrout just made a little promo video about the whole thing that I can send you a link to as well that has a bunch of imagery and stuff. So, if you want to check that out, I'll put a link in the description.

HAMANN:

Awesome. Yeah. And then, you know, along those lines, if there's links to other websites or partners that you want us to include in the show notes, please include those and we'll make sure everyone gets their due credit.

ROSSI:

I know I was like hoping we got all the names right. There are truly so many people involved and I hope we didn't leave anybody out. I think we did a pretty decent job covering the bases.

WHEELER:

Well, with that, we can call it an episode.

HAMANN:

Yeah, thank you all very much. We really appreciate hearing about this exciting project. Thanks a lot for having us on. Folks, if you're out in the South Fork and you see a fence in the river, don't worry, it's there for a good purpose.

WHEELER:

This has been another episode of the EcoNews Report. Join us again next week on this time and channel for more environmental news from the North Coast of California.