Research shows change in fish larvae due to warming waters
Dr. Rebecca Asch, a professor at East Carolina University, discusses recent research that looked at fish larvae (juveniles) in Beaufort and the pattern changes happening due, in part, to warming water temperatures.
Uh, okay, So, um, I'm excited to get to talk to you a little bit today. Dr. Rebecca ASHA, professor at E C. You and your lab focuses on global environmental change and ocean ecosystems. And I was just kind of looking through my twitter feed yesterday, and something jumped out at me, um, about an article on some of the work that your lab has done, and it just seemed really cool. And any time that I could do a climate change story and bring it back to North Carolina for our viewers, You know, sometimes it's a little obscure to talk about the melting ice. Um, and that kind of thing that you know, it's far away from what we're dealing with here at home. So when I saw this about fisheries and North Carolina potentially being impacted by rising sea surface temperatures in different, um, different things that you looked at regarding that I thought it was interesting. I thought probably our viewers might be interested in it as well. So tell us a little bit about the study. What fish species were you actually looking at? And where here in North Carolina? Yeah. Thank you for that question first I do want just mentioned that this was a study where the lead author was a graduate student in my lab. His name's Christopher. Thank faxed AnAnd, and he graduated recently from East Carolina University. And what we did with we were collaborating with a lab run by the National Oceanic and Atmospheric Administration, which is out of Beaufort on North Carolina. So that's kind of area that we were focused on and that labs been looking at Fitch Larvae right outside their lab, sampling them for a bridge since 1986. So we analyze that data set, and we found that there were 10 species that had enough data that we could really look at friends. Um, and when they occurred, um in these species were, if some that are commercially important, where some are just fish species that are common. And there was a lot of data on. So we had American eel. We had men Hayden spot, croker pin fish. Um, mullet was another one. Also a speckled worm eel, which is, you know, small fish. That's not really important for fisheries, and then three different types of flounder or as well, and um you found that basically, because the temperatures are getting warmer, the sea surface temperatures are getting warmer. Our seasons are a little bit different now. Summer last longer winters are shorter. What did it do to the amount of the fish larvae that you found? So we were looking at basically amounts of fish larvae occurring. This, like data set, is weekly sampling. So we looked at basically amounts of larvae happening in different weeks. And whether that was shifting in one direction, Thio either have fish arrived earlier or later. And what we found is if you look at this community of fish as a hall, on average, they were lifting to enter the asteroid earlier, but there wasn't really exchange in when they stopped arriving. So you had a longer season of them entering the estuary and potentially using the habitats air. And do you know, um, I'm not sure if you've actually looked into this or not, But does that change anything with those fish that you were looking at? Does it change like their size? I know Here in North Carolina, I think the law for flounder is 15 inches. So does it impact the size or the growth with them being in those areas a little bit longer? Um, it very much could. And I think that's kind of the area that we're playing toe Look at next. So basically, this cup study looking at larvae. That's a really important life history stage that can influence growth and can influence basically how many fish kind of grow to be large enough to enter fisheries. And while the ways that it can impact them is often fish spawn and reproduce a particular time of year to make sure there's did not pray available for their offspring. So if there prey items or not changed and when they're in the estuaries that could there was a mismatch between one larvae or their and when their prey or there that could affect growth. And we're actually starting to survey some of the plankton to try to look at that. The other other thing is that they use the estuaries because there's a lot of habitat that can put take them from predators that include things like seagrass habitat and salt marsh habitat, where they can kind of hide, um, to get refuge, and a colleague of mine has been working on basically looking at changes in seasonality of seagrass in some of the same areas, and they are finding some changes in the seasonality of seagrass that could affect how much protection there is for the fish when they move into the estuaries. But again like this is the area where we would probably need to kind of combine those data sets to really understand how this adds up to impact fisheries. So there's lots of exciting things to follow up on. Yeah, interesting. That's that's kind of how research works. You kind of study one thing, and it leads to all these different, um, avenues. I know that with my husband being a research professor over at N. C. State. Um, question on the sea surface temperatures, What have y'all noted? Like, What are the changes in the sea surface temperatures in that area? Is it dramatic? Um, what? What numbers are you seeing? So looks like one of the things that was interesting in surprising about this study. Because there's been some firework that suggests at least compared thio areas north of here. Temperature hasn't changed quite a much in the estuaries and offshore. Aziz in other parts of the US So when we started this summer study, some my colleagues were like, Okay, that's worthwhile doing but you might not find a change is because temperature hasn't changed all that much. So that was like one of the things that we were a little bit surprised about, because the changes have been smaller than other areas. But the Fisher still reacting to the changes that have occurred even though they're fairly small, just it just takes a small change for it. Thio. Make them change their habits, I guess. Which is interesting. Yeah, I think the part of this is related to the fact that you're in North Carolina were in a really interesting region in terms of the ecology. So there's different zones where you'll have, for instance, like tropical temperature, temperate or polar species. And we're kind of intersection between two areas between, like where you get more tropical and sub tropical fish and fish that have occurred in the middle, like the mid Atlantic and ah, lot of those tropical species will get into our waters, but they won't necessarily survive the winter, so it might be that these small changes or just allowing fish that can make it into our waters have better opportunities to survive because there's less kind of cold snaps over the winter, which can really affect, um, their survival when they're kind of young fish, juveniles and larvae. What would you say to somebody who is, um, you know, somebody that frequents the coast to go fishing? Maybe it's their career, and they depend on that. If they hear this and they're like, Well, this is great news, warmer waters, they're going to thrive. This is actually really good news. What would you say to people like that? Well, I think it depends which species you're looking at in which species you care about, because there's definitely, you know, with climate change for most species. When you're looking at a community, you're going to have winners and losers. So I think that is, temperatures change. We might have mawr kind of tropical fish, but we're going to have less temperate fish. So I think one of the species that we looked at the study that's had some large changes. Its distribution is summer flounder or and it's a species that, you know, North Carolina is kind of the southern part of its range. So we're seeing less of that and maybe mawr of other species that are more tropical. So it's in this case that's about it's about change. And I think people who live on the water and depend on these resource is need to be able to adapt to some of these changes. And also management needs to be able to adapt because they'll happen. And there might be advantages and opportunities where for other species, there could be loss of that species in our water, right? And I guess studies like this could lead to changes in the policies and the way we handle things. Um, like, if our fish population of flounder were thio, get smaller and smaller, I assume we'd have to change. You know how much of those we could actually fish here? Yeah, I think it's really important that in terms off management regulations that they're basically kind of adapted to changes both in the resource and climate. And, you know, studies like this might allow us to be a little bit more further looking in terms of anticipating what changes we might see in the future. Um, what other things do you have from this particular study that you think that our viewers would find fascinating? Are there any other points of interest trying to think a little bit about that? I mean, I think that stop. It's just that for certain species of the changes are quite large. So there's a couple of cases where we're seeing changes where things are entering the water, you know, two months earlier than in the past. So I think that was kind of one of the things that was highlighted. The other thing that is kind of interesting is we looked at, like a basically both changes in temperature and wind patterns, and some of the changes that we're seeing are equally affected by temperature. And when so, you know, it's kind of like one of these things were it's important to recognize that variations and changes in climate can be multi fascinate, faceted and can affect the ocean in different ways. Um, yeah, I think I read that you found that there was more of a northerly wind. Um, I remember that. Yeah, eso basically what we looked at is basically if winds were blowing from the north to the south that is going to make it harder for, like the larvae to enter the estuary just because in both for like the estuaries oriented to the it's entrance is towards the south. So it's basically kind of essentially blowing them out of the asteroid. And if that increases, that's going to cause delays in, like when the fish came, Enter the estuary and you said that one of the species is entering it as much as two months sooner now. So what does? Does that do anything to that particular species? That what does that mean? It it's coming in two months earlier. What exactly does that mean? So I think that it's all kind of like related to the fact that what's going on with its prey is probably quite important. It probably means that that species is reproducing earlier in the year, and if its prey is doing the same thing and changing its seasonality, then perhaps this is all going to be good. Whereas if it's prey, items are doing something different than like you could have basically this fish reproducing, entering mastery, expecting there to be playing of food for its offspring, and there isn't so again like That's kind of like the next question that we're really trying to answer. That's interesting. That's really cool. I look forward to hearing what you find, um, assed faras. That aspect goes as you continue going down different paths and seeing what else you find, Hopefully we'll see some of those stories showing up on Twitter again. And we can reconnect and talk about those as well. Thanks for joining me today. I really appreciate it. Oh, thanks so much. And yeah, looking forward. Toa in the future talking to you about those subjects. Awesome. And if you ever have any ideas or you ever have any research that you could share with us about climate change, just send me an email, and I'm happy to cover it. Love sharing that stuff with our viewers. Traffic. Thank you. All right. Thank you. Have a good day. You too.