Climate Change, Coastlines, and Aquaculture

How is climate change affecting our coasts and ocean? What about aquaculture? Halley Froehlich, an expert in climate change impacts to coasts and oceans, with a strong focus on aquaculture, joins us to discuss this important topic as we wrap up our series highlighting Key Messages in the Southwest Chapter of the 5th National Climate Assessment.

Relevant links:
Read the 5th National Climate Assessment (NCA5)
Webinars and podcasts on the NCA5
NCA5 Atlas

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DOI Southwest CASC: https://www.swcasc.arizona.edu/ 
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Transcript

Welcome to Come Rain or Shine, podcast of the USDA Southwest Climate Hub and the DOI Southwest Climate Adaptation Science Center for Southwest CASC, operated by the USGS. I'm Sarah LeRoy, Research Coordinator for the Southwest CASC. And I'm Emile Elias, Director of the Southwest Climate Hub. Here we highlight stories to share the most recent advances in climate science, weather, and climate adaptation and innovative practices to support resilient landscapes and communities.

We believe that sharing some of the most innovative, forward thinking, and creative climate science and adaptation will strengthen our collective ability to respond to even the most challenging impacts of climate change in one of the hottest and driest regions of the world.

The contents of this podcast are for informational purposes only and should not be interpreted as endorsement for any of the products, technologies, or strategies discussed. 

Emile: For our final episode in the series discussing the 5th National Climate Assessment, we will be focusing on the region's coast and ocean. As a reminder, the 5th National Climate Assessment, or NCA5, is the U. S. government's preeminent report on climate change impacts, risks, and responses. It's a congressionally mandated interagency effort that provides the scientific foundation to support informed decision making across the United States.

Today we will be speaking with Halley Froehlich, an expert in climate change impacts to coasts and oceans, with a strong focus on aquaculture. Halley is an assistant professor at UC Santa Barbara and was a contributing author to the Southwest Chapter of the National Climate Assessment. Thank you. So much for joining us today, Halley.

Halley: Thank you so much for having me thrilled to be here. 

Emile: Great. The key message, the second key message of the Southwest Chapter states, adaptation efforts increase to address accelerated impacts to the region's coasts and ocean. Can you tell us the main points that this message conveys? 

Halley: Yeah, I think kind of first and foremost within that key message is that we're seeing effects now. Right, this, this isn't a future storytelling kind of message, this is we're seeing the effects now, including regions like California, which is, as you noted, where I kind of focus my efforts on the most recent NCA. And in California, it's kind of unique because we have both the telltale Southwest impacts of climate change, drought being one of them.

But we also have our massive coastline that then we have ocean based processes and impacts occurring like marine heat waves. as well. And then on top of that, in places like California, it's highly, highly dense, and it's a huge economic driver in many senses, including agriculture. And so you end up having kind of this, uh, consortium of really important things, resulting in the push for adaptation.

So in other words, California really can't risk not doing anything, um, because climate change is bearing down. And so California is kind of leading in many ways in that charge. 

Emile: Excellent. Thanks. And I'm curious about, so you worked with other authors on this as well, and I'm curious about how you determined what was the most important topic or statement to put into this key message?

Halley: Yeah, certainly the kind of synthesis of the standing literature of kind of going through relative to past NCA5 was super helpful in determining that phrasing but kind of more broadly as you noted of the collective knowledge of the people in this chapter and across the various chapters, um, was really critical in that framing of where does kind of California sit in the bigger scheme of things?

Is it doing more or less? And for the most part, we see in many instances, California, again, kind of leading at that adaptation edge relative to climate change. 

Emile: Great, thank you. So one of the findings in this section of the Southwest chapter is that human caused warming contributes to marine heat waves, or incidences of exceptionally warm ocean temperatures, and those have already had significant impacts on human and natural systems. So can you tell us more about past observed marine heatwaves and the impacts of marine heatwaves to ecosystems and to people? 

Halley: Sure, so marine heat waves are kind of an interesting one because they're a relatively recent designation within our realm of climate threats or impacts in the oceans anyway, and while variability in thermal temperatures or things like that is not a new idea, of course we've been studying things like El Nino for a very long time, but now we have this kind of new appearance of intensity, of frequency, extent, and magnitude of warm temperatures, even outside of the natural variability that we have been studying and seeing.

So from that perspective. This is kind of extreme conditions that we see in the ocean, kind of parallel to the extreme, I suppose, drought that people study on land. And the kind of important part here is that that's getting kind of bolstered by things like the average warming temperature that we're seeing over time as well.

And so some of the kind of the big things that really set into motion to understand and study the consequences of these marine heat waves really kind of came to a head around the kind of 2014 to 2016 time period where Maybe some of the listeners have heard the term The Blob, which was this massive ocean extent that just got really, really hot, kind of started in the Gulf of Mexico, and then expanded down the entire West Coast to Washington, Oregon, and California, and stayed there for years.

And I should say, marine heat waves, the way that we're classifying them now, can be days. to months, to weeks, to years. And this one was a really, really intense one that lasted an exceedingly long time over an insane area of the ocean. And we saw the rippling effects of that. So some of the big ones were things like the one that's most notable and garnered a lot of attention because it both impacted wildlife and humans simultaneously was that there was a spatial and temporal overlap of important things like whales following their prey that were getting squeezed by that heat that ultimately then overlapped with important Dungeness crab fishing area.

And so we saw entanglements and That resulted in, um, delays and closures, um, around the Dungeness crab fishery and had dramatic impacts associated with that. We, of course, saw a suite of other things associated with it, not just related to whales and fisheries. We saw evidence for changing species composition of more kind of thermal tolerant organisms being more abundant.

And we also saw changes in abundance and quality of important prey species, um, having potential trickle down or trickle up effects, if you, if you will, on seabirds and mammals. And we also saw a complete kind of wipe out of things. Um, that we connected later to marine heat waves, um, specifically that of almost complete loss of bull kelp in Northern California.

So really kind of impacting a little bit of everything across the ecosystem, um, and trying to kind of keep track of everything from the small things that, um, organisms like to eat up to the really big things we care about like whales, um, and then of course fisheries. 

Sarah: Thanks Halley and thanks for joining us today.

So, building on that, another impact that is mentioned in this key message in this office chapter relates to harmful algal blooms. So how is climate change affecting harmful algal blooms or HABs? 

Halley: Yeah, so it's kind of adding insult to injury. Harmful algal blooms, uh, we've now seen some linkage to them in relationship to warming conditions.

Um, the reason they're called harmful, because typically they're related to toxins. Um, so the little plankton that are growing in there, usually diatoms, can potentially produce, um, toxins like domoic acid is probably the most common one, um, that you see in something like the news. And these harmful algal blooms ultimately can then impact usually shellfish.

Again, we're talking about Dungeness crab or lobster fisheries, where this domoic acid increases, these organisms consume that domoic acid, and while they're not directly affected, if animals like higher level seabirds or marine mammals or people eat them, you can make people really sick, um, it can result in seizures and memory loss, and under kind of, um, really severe conditions, even death.

So it ends up being really important, um, in terms of controlling these things. And so when harmful algal blooms happen, usually what we have again, are closures, delays, um, and things of that nature. 

Sarah: Thanks. So let's talk about some solutions to these things. They're pretty negative. So what are some adaptive approaches to fisheries management, you know, due to the widespread impacts that we just talked about related to marine heat waves and harmful algal blooms?

Halley: Yeah, absolutely. And I should mention that when we're talking about solutions, like it's, it will be very different for the type of sector or the scale that we're talking about. So some of the important things of like the trends that I'm describing, especially when Right now the negative ones are being not just reported in the westernized scientific context, but also we're seeing that, that type, those types of trends and reporting from, um, traditional tribal knowledge as well across the state.

So this is something that is impacting commercial scale and tribes and small scale fisheries and recreational, like it really spans. And so the solutions that are potentially there can differ. Um, but some of the things at kind of the high level that we're noticing for adaptation to these impacts, um, tend to span from individual or sector level, uh, which is pretty common, um, up to potentially larger governance changes.

More commonly, what we see is this kind of incremental or reactive change, um, in the, in the adaptation scape. So you can think of something like fishermen following the fish, uh, because it gets too warm and so they move. That is super common. Fishermen are really good at kind of turning on a dime and following where the fish are.

So that's pretty common what we see. We also see, um, some kind of higher level, maybe strategic or systemic changes that, that have been implemented at the governance level of allowing flexibility for fishing different species. So if one is heavily impacted, a fisher can fish something else, and we see that as a really common response, not just to these kind of climate changes, but historically, uh, when fisheries kind of fluctuate, being able to change that helps.

However, the kind of larger, transformative, really planning for these things and coming down the pipeline for something like fisheries, is not implemented or as common, um, as it potentially should be for some stocks, um, or approaches. So I should say that the Fisheries Management Council on the West Coast, um, has adopted a fisheries ecosystem plan that accounts for things like, or at least provides guidance to what to do under ocean acidification, uh, or hypoxia, IE low oxygen conditions, but kind of more flexibility and, um, kind of, again, larger planning and applications of, say.

Adaptive control rules, uh, where it can basically go up or down more readily if systems change really quickly like a marine heat wave. That type of responsiveness isn't so much there yet. 

Sarah: Thanks Halley. So you just mentioned ocean acidification and the chapter, the key message in the Southwest chapter goes into this topic as well. So could you tell us a bit about ocean acidification? 

Halley: Definitely, yeah, so. Ocean acidification, more fondly known as OA, in the scientific literature because we love our initializations. So OA in climate change is the partner in crime, I would say. So OA is the process by which the ocean is kind of sucking up carbon dioxide and ultimately forming carbonic acid, and that's what ultimately is acidifying the water.

This is inherently problematic, uh, because things that form shells ultimately need to have access to carbon forming molecules, um, and that acidity just makes them inaccessible, um, and so they can't form their shells properly, so we're thinking, like, uh, plankton and larger organisms like oysters. So this kind of really starts expanding and affecting things like aquaculture and fisheries and ultimately is one of the most heavily studied areas, I would say, especially from a aquaculture perspective.

So we're going to move outside of the chemistry and the partner in crime, maybe to the mob boss. So sea level rise. Uh, something that's also mentioned in the Southwest chapter and it poses risks to oceans through an increase in flooding, impacts from storm surges, and a loss of coastal habitats. So can you tell us a bit more about sea level rise and again, the role that adaptation planning has played?

So I will do my best to reflect on this particular topic because this was actually led by Leah Um, at the Department of Transportation at the time, so I will try to convey her contribution the best I can, uh, but full disclosure, I am not a sea level rise expert. But, uh, it is a really important aspect, and I think one of the areas that is being tackled more sufficiently, um, than maybe some of the other areas that we've talked about so far.

So, lots of people in California, like many coastal regions, live near the coastline, and so this impacts a lot of people, potentially. Um, and importantly, at least what the scenarios. that have been run for the specific region, um, in California are showing, and it, it, it's pretty mind blowing, especially because I tend to operate more in the thermal and OA land, um, That across all scenarios, there's impact, um, and that's not true for a lot of other scenarios and other reaches, but sea level rise is kind of a consistent one that we can anticipate to see kind of increases, um, of effects from tide and storm surge events.

Um, that are anticipated to become more frequent, um, and severe into the future. And on top of that, we see pretty strong evidence of that already starting to occur right now, though again, not at the severity yet. So because it's already coming to fruition, and that it would affect a lot of people in low lying areas, especially if we're talking about impacts on energy, on transportation infrastructure.

It can also taint groundwater. Um, it can also impact kind of water quality in general if it potentially impacts industrial areas, spreading contamination in different locations. So it really has really far reaching effects in many, many different ways and usually to poor communities as well. That, uh, the things like the California Department of Transportation, um, has begun implementing adaptation planning, uh, efforts to consider a variety of different strategies of not just, say, hardening infrastructure, which is kind of our go to.

Um, we like to tech our way out of things, um, a lot of the time. But we're also seeing now inclusion of more nature based solutions, um, things like protection and improvement of wetlands. For instance, um, and so we don't just have massive runoff or huge, uh, deluge, uh, of, um, surges coming in. There's natural systems that can buffer that, that we know from just base ecology and, uh, biology that can help as well.

Emile: Excellent. Thanks for talking about sea level rise, even though Leah led the charge on that in the chapter. And now we're going to move back to your research. So one of your main areas of research centers on. Aquaculture or aquatic farming. Can you describe aquaculture for our listeners? What is it and how prevalent is it in the Southwest region?

Halley: So aquaculture, as you said, it's aquatic farming or the farming of aquatic organisms at some point at their life history. Aquaculture is extremely diverse and it can look like a variety of things, but For all intents and purposes, it's kind of like if you think about how we grow a pig or a chicken, right?

We're not relying on wild sources of those things, at least in the United States and in many other countries around the world now. Instead, we kind of, we farm. We contain the, the life stages and we grow them out, typically for food. And so aquaculture is kind of the same idea, except we do it in water instead of on land.

In the US, on the whole, aquaculture doesn't play a huge or as huge a role in the type of aquatic food. We can also call it seafood that is produced. However, it does play a large role at the global level. And although it's not massive in the United States, um, some of our work is showing just how ubiquitous and actually much larger, uh, than we actually think it is, uh, because it is, it, it's falling behind or has fallen behind its larger, uh, comparative sectors of agriculture and fisheries and haven't, hasn't garnered as much attention, but that's changing quite a bit, um, with people looking at the trends of aquaculture and that kind of thing.

untapped potential, if you will, um, related to it. So we're seeing growth, um, and interest both in kind of the freshwater area, but certainly in the marine space as well. 

Emile: Excellent. And this is a really broad question, but because you researched this topic, uh, I just want to give you a chance to expound on this. So why is aquaculture important, especially in a changing climate? 

Halley: And like I said, it's not hugely produced in the United States, but it makes up half of all production of seafood globally. So it is now a major form of how we get food. And like I said, there's kind of garnering interest in kind of expanding it certainly by the USDA and NOAA as well.

And it ends up being, even though we don't grow it personally, uh, in, in our nation. A lot, we do depend on it from other sources. Seafood is one of the most traded commodity items in the world. And so from a climate change perspective, what's happening here and what's happening in other reaches of the world and how climate change is going to affect that production and what the solutions look like are going to differ and have far reaching impacts because of the dynamics of how we produce the food and trade it now.

Sarah: Thanks Halley, and you just touched on this, but how is aquaculture changing due to climate change? 

Halley: Yeah, so aquaculture, it's one of the burning questions that I am constantly trying to answer. Some of the work that I've done has shown that aquaculture is, and climate change interactions, is one of the least studied, and so there's a lot of gaps to be had.

That said, the things that we do know about, especially if we're focused on the United States, tends to revolve around ocean acidification. That's the primary form that garners most of the attention, and it's not really surprising. For most of, say, marine aquaculture, the, the targeted production system are oysters, so shell forming organisms.

That makes up the bulk of what we produce in, in ocean waters. And in fact, We only really know about ocean acidification is because a farm up in Washington kept losing small little juvenile, um, young of oysters one batch after the other and they weren't sure why, and it was ocean acidification. So they were kind of the canary in the coal mine in terms of us even knowing that this was going to be important or that we should study it and so it logically has taken a lot of that, that space and trying to understand those processes.

But obviously, there are a lot of things that can potentially impact aquaculture, including things that we've already mentioned, marine heat waves, or just changing average temperatures, obviously impact things like growth and disease and mortality, sea level rise, So, Could certainly impact infrastructure that aquaculture is dependent upon, but unfortunately, we just don't fully know what the snapshot looks like, especially as we downscale from global models to more national to definitely more local, regional implications.

So some of the work that myself and my lab are trying to do. is fill in those gaps to try to understand it, um, because as people start investing in this type of potential production, especially for marine siting of things like offshore aquaculture that is being designated now in various areas. it does not include considerations for climate change.

So that might be a problem or it might not be, right? We don't know, which is really hard to say, then, um, how climate change is going to impact aquaculture because it's really going to depend on species and siting and capital and people, right, of accounting for all these different variables and we're just now starting to try to fill in those gaps for it.

Sarah: Great, thank you. So, I mean, we just talked about how climate can impact aquaculture, but aquaculture can also impact the ecosystems of, you know, where the, the organisms are farmed. So can you tell us about how, how that happens? 

Halley: Yeah, so it is a food system. So it will have impact. That's how I always start this conversation, um, with aquaculture because it definitely, I would say it has a bad reputation, um, especially in the United States of eat wild, not farmed type of dichotomy, which arguably doesn't really exist if you include hatcheries, but that's another story in a different podcast. Um, but yes, aquaculture absolutely can have impact, especially if it's poorly planned and poorly cited and unregulated, like most industries, food or otherwise. And the kinds of things that we can see is increased prevalence of pollution.

So that could be either kind of from the organism that you're producing, so effluents, which is just a nice way of saying fish poop, um, or you can have, uh, of course, plastic waste and all the kind of associated waste, um, around industry being operated in, in an environment. Certainly, Proliferation of disease is a major concern with aquaculture.

Like most farming, you tend to raise up that carrying capacity in a given system because we can intervene and fit more into a small space, um, but that has trade offs because that also is a lovely environment for diseases to, to increase. related to density. And of course, interactions with wild species.

And that can take many forms. It can be entanglements, potentially, although we don't have really strong evidence of that being as much of a problem as it is for wild capture fisheries. But still, not zero. Wild organisms like to interact with it. Uh, one, because you can have predators being interested in this nice buffet that has been placed in front of them.

Or if things that, for instance, salmon or salmon fisheries are really concerned about. is that interaction and transference of disease to wild organisms as well. So, All of those things can transpire, especially if it's a poorly managed system, but the kind of key to that, like most things, is better management and best practices.

Emile: Thanks, Halley, and you started getting into moving towards my next question. I really like that you, how you framed it, um, as you're talking about this. It is a food system. It will have impact. And so, I'm wondering about any solutions to these impacts, and you started going in that direction. Are there any others you'd like to mention?

Halley: Yeah, there's lots. Lots of potential interventions, and they are many. And some of them are already in the existing regulations that we have, including things like water quality control, right? Aquaculture in the United States falls under that and has to be managed appropriately. Okay. in those types of regulations.

Best management practice documents that are either mandated or not exist. Across many, many different areas, either at, have been provided at the national level or can be state specific. Lots of variability there, like I said, existing regulations that are already in place, lots of differences depending on what state you're in that can dictate the type of species that's allowed, the density that's allowed, the types of treatments of things like antibiotics, which for the large part in the United States are not allowed in open marine environments. Um, so more commonly we'll see vaccines, for instance, to deal with that or other control factors to deal with disease.

And so I think the key is very much capacity and enforcement for a lot of these things. Um, and the kind of, important part, I think, that weaves together some of the conversation about climate change. is that these kind of approaches likely have to be modified or changed under climate change. Um, again, and we're just now kind of scratching the surface and trying to understand, um, what this looks like, especially for things like temperature and disease based occurrences, for instance.

Emile: Great. Now this next question is for our listeners who like to eat seafood. So we know that climate change and human consumption are impacting the wild fisheries. At the same time, aquaculture globally can, you know, provides food for, you know, 50 percent of the world. I think that's what I heard you say, can also have impacts on ecosystems.

So for people who want to consume seafood, but also in a sustainable way, what do you suggest? 

Halley: Yeah. And I get that question quite a bit. And I would say my answer is kind of the same for wild as well. Aquaculture and fisheries are kind of one. of the same coin, you know, so this is especially true because now it's seafood is very much wild and farmed.

Um, given just the prevalence and the types of things, if we're talking about United States, of the things that We like to eat here, which are largely the top ones are shrimp, salmon, tilapia, catfish, and all of those are largely farmed at this point. If you eat those things, you most likely are going to be eating a farmed product.

And so I would suggest a couple things. One is local is likely good. The United States has pretty good regulations around both wild capture fisheries and aquaculture, and there are a variety of farms, say if we're talking about the Southwest, across California that produce aquaculture, both from things like bivalves, mussels, oysters, things like that, and seaweeds.

I should say the, the unsung hero of the aquaculture sector, the seaweed, the mighty seaweeds, in addition to things like caviar, right? California boasts the largest production of white sturgeon in the United States, which I don't think a lot of people know. And so, Thinking about where your source is coming from and thinking about or trying to connect to either your local fish market, or you can actually, a lot of regions have delivery options.

We actually have a company here called GetHooked. That connects local fisheries and aquaculture farmers products to direct to sellers, or consumers, excuse me. And, but if you're feeling kind of like, uh, I don't have time, um, to be going to the fish market at six o'clock in the morning on a Sunday, which I think is probably most people, I can certainly attest to, even though I love seafood, I have a one year old, so doing that is basically impossible.

For a clear signal, say you just go to a grocery store, you can also look for certification of things like the Aquaculture Stewardship Council or Best Aquaculture Practices, ASC and BAP. And while not perfect, uh, they try to kind of simplify and certify, um, farms that are doing a little better. There are also similar certification programs for wild capture, um, as well.

Sarah: Thanks, Halley. That's especially appreciated for us who live inland and cannot go to our local seafood. Market in the morning. Um, so I appreciate that. So we talked a lot about, you know, adaptation strategies and solutions. And, um, we like to ask all of our participants here, you know, what gives you hope for the future? So that's my question for you. What gives you hope? 

Halley: So I think what gives me hope is The interest in fight in the next generation. Studying something like aquaculture can seem irrelevant or maybe inconsequential at times, especially given things that are occurring, both. in the United States and globally, but I would say what I find, especially talking with my students, there is this kind of growing and seen potential for aquaculture to be part of the solution instead of just the problem.

Um, if we look at things like seaweeds or low trophic level or low impact organisms and, um, Thinking about how that ties into climate change, whether that's nature based solutions, which are starting to gain traction. I think that, for me, is really exciting and gives me hope, is that there's these solutions that are really tangible, um, and can feed back into things of adding Resilience or adaptive strategies to the things that are linked to climate change within the food sector, and I feel like students are very much excited about that solution oriented space, so we've been hearing impacts a For so long, and the science is very clear, that climate change is here, humans are the primary driver, um, and here are all the terrible things that are happening, and I'm finding, for the most part, um, the younger generation is like, yep, we see that, now what do we do?

Um, and so while this is a little slice, there is a very clear intersection, um, with climate change solutions, especially, um, from a food, food dimension. That's perfect. 

Sarah: Thanks. Uh, so lastly, we just want to leave and ask you, what's one thing that you would like people to remember from this podcast? 

Halley: I would say maybe aquaculture is small but mighty, um, is, is my take home and that we're just scratching the surface, really, of its role in the broader food system of, it's been this kind of under the surface, it's always been there, but now people are like, wait, what is this?

Why is this here? Why is this? Oh, oh my gosh, it's everywhere, and nearly in every single state of the United States, on our coasts, inlands, it's everywhere, um, and so that intersecting with what does that mean in the face of climate change? Yeah, I think that's the big one. 

Sarah: Well, thank you so much for joining us today, we really appreciated you sharing your knowledge around NCA5, but as well as your, your vast expertise on aquaculture. I learned a lot and I know our listeners did too. So thank you. 

Halley: Yeah, my pleasure. Thank you again for having me.

Thanks for listening to Come Rain or Shine, podcast Southwest Climate Hub and the USGS Southwest Cask. If you liked this podcast, don't forget to rate or review it and subscribe for more great episodes. A special thanks to our production crew, Skye Aney, and Reanna Burnett. If you want more information, have any questions for the speakers, or would like to offer feedback, please reach out to us via our website.