Podcast

Zebra Mussels – Spreading Through Our Waterways
04/02/2021

Zebra mussels are not new to the U.S., but they have been featured in the national news as of late for a new reason. They are one of the most invasive and destructive species in North America. Recently a new way of introducing them into even more of our lakes and rivers has been identified. And you could unknowingly be contributing to their spread. AJ McDade chatted with CEC’s Cameron Lange, a nationally recognized nonindigenous, aquatic nuisance species expert, to learn a bit more.

Podcast Transcript

AJ: You’re listening to CEC Chats. Your quick hit on trending topics from the worlds of engineering and the environment, brought to you by Civil & Environmental Consultants. Today we will be chatting with Cameron Lange, a nationally-recognized non-indigenous aquatic nuisance species expert about zebra mussels and how many of us may unknowingly contribute to their impacts on our water bodies and industry.

Hello, Cam and thank you for joining us.

Cameron: Hi AJ. Glad to be here. I’ll give you a little bit of my background first, before we get into the topic of zebra mussels. I guess it all started way back when I was a young child and mucking around my uncle’s farm pond with a small net and boots picking out whatever I could find from newts to leeches, unfortunately, and a bunch of other organisms trying to identify them. Jump ahead a little bit to after I graduated from college. My first work was with a small environmental firm doing aquatic ecology, looking at the impacts of power plants on the environment. Doing fisheries studies, looking at the ichthyoplankton getting drawn into the plants, etc. One Night in 1985, I was sampling the traveling water screens for fish and noticed that they were all fouled with a gelatinous coating which I didn’t know what it was. Nobody knew what it was. So we took it off the screens put it under a microscope and lo and behold it was an organism called bythotrephes cederstroemi, which is related to a daphnia that you find ubiquitous in the United States. But it turned out that it was imported from Europe. Based on that, I was lucky enough to publish in a small journal article and it really piqued my interest in non-indigenous species.

Jump ahead about three years, I was doing a study in Lake Erie collecting fish around a nuclear power station for radiological testing. And the plant biologist, the facility biologist, who happened to be there, she said hey look at these things and there are small striped what she called zebra clams and say those are pretty cool things, you know didn’t think much about them. Two months later the news broke that they’re spreading and what their impacts were. Since that time in 1990, I have done numerous zebra mussel related activities. We started off in the zebra mussel game by watching their movement across New York State’s barge canal system looking at their distribution from month to month to see how they entered other systems including the Hudson River system in the Inland Lakes and published papers on that. It was quite interesting how they how they moved not only via veliger distribution, which we’ll talk about a little bit, but as adults being transferred on boats. From there, I joined what we call the traveling road show. I was in New York State Sea Grant Training Session where we presented a two-day informational sessions to interested in parties, and I think it turned out to be about 42 or 43 of the states providing information on what the zebra mussels were, their backgrounds, how they spread, what you do to control them in various settings, etc.

I’ve done a lot of vulnerability assessments where we’ve taken a look at water bodies and seeing whether zebra mussels would get into the waterways, if they got in how likely they were to proliferate based on the water chemistry. Although people think zebra mussels are these super organisms, they actually only thrive in a fairly narrow range of environmental settings. They need sufficient calcium, they need a suitable water temperatures, high water temperatures will kill them lower water temperatures  they won’t be able to propagate they need the correct PH, and need quite a bit of food as they undergo their transformation from their from their larval stage to their adults. So we did a lot of those types of studies. The other component of vulnerability assessment studies were taking a look at individual facilities, the power facilities, that would be impacted and see how they would impact the facilities what you could do to keep them out or prevent them from becoming a problem. The most interesting types of work that we did were actually sponsored by the Corps of Engineers and other, some utilities and power facilities, etc., were research and development projects, where we looked at non-chemical controls, novel approaches to mitigate zebra mussels within the facilities without causing environmental harm. Basically you can kill zebra mussels by dumping chlorine on them. That can kill most organisms, but when you put chlorine in a flow through type of system where the zebra mussels become problems you will have additional problems at the release of chlorine into the environment. So that’s a little bit of my background. I’ve been working on them for 40 years now.

AJ: You’ve come a long way since playing on your family’s property. So, what I find really fascinating Cam is that back in December you and I got together to write an article for Elements magazine to discuss zebra mussels and how they affect waterways and industry and then here we are getting together so soon how fortuitous that we would have known that right now that zebra mussels would be in in the news again.

Cameron: Yeah, that’s right. They seem to crop up when you least expect it over the years and a number of times they’ve they become newsworthy. That’s not to say that they haven’t always been and continue to be a nuisance and impact various water users.

AJ: Now I definitely want to talk about that. But before we do, why don’t we share with our listeners a little bit about the history of how zebra mussels came to the United States.

Cameron: They were first found in 1988, which led people to believe they were introduced some time in 1986. A transoceanic freighter came in and released their ballast water into the St. Clair River near Detroit, Michigan, which is part of the Laurentian Great Lakes chain, they were probably released as their young veliger stage, which is a young planktonic stage that is free swimming, it’s microscopic, it settles and then grows into adult mussels. From there, multi generations later, they spread throughout the Great Lakes. We did a study of them entering the Erie Barge Canal system into the inland waters of New York State. They also entered via the Chicago Ship and Sanitary Canal, which is a water body I didn’t know about, but it connects Southern Lake Michigan to the Mississippi River system. So they spread rapidly through the currents downstream to all the way to New Orleans, Louisiana. Very, very, rapidly. They were brought then by barges up into the various other tributaries of the Mississippi River system. They also jumped, and that way they got up into the Ohio River system also, and up to Pittsburgh. And from there, they hopped into various inland waters via boats and other various means of transportation.

AJ: Now, you mentioned earlier that they need the right conditions in order to thrive. So, the waterways that you are mentioning, did they just roll the environmental dice? What makes these waterways that you’re talking about, where they first were introduced to the United States, a proper environment for their development?

Cameron: I think saying rolling the dice is probably correct because they just happen to have the right environment. The zebra mussels were probably introduced long before they became a problem in the United States. You look in the literature and they were predicted had to have been introduced way back in the 1920s. Although they never came here. They were probably brought over, dumped into a lake or river without the proper water quality or the proper numbers of organisms, so they just didn’t take hold. Everything was lined up, all the stars lined up with the amount of introduction and the water quality so they could spread.

AJ: So, fast forward, they are now here. They’re in our waterways. What industries do they affect and how?

Cameron: Okay, there are two major groups that they affect. First there are the industries, the industries include the hydroelectric facilities. They include nuclear power stations, they include fossil stations, they include drinking water folks. They include anybody that uses water from an infested source, drawing it into their systems. The other major effect that they have is on the ecology and on the environment. They are small. A single zebra mussel, you wouldn’t think much of it. It’s basically about two inches long, you know, it’s just it looks like a little clam and it’s not much to speak about but each one of those individuals can filter a liter of water a day. They go about their ways of drawing things in and releasing waste, use oxygen, etc. And you multiply everything an individual does by about 200 to 400 thousand individuals per square meter, which is a typical coverage in an infested water body and they can do a lot. Some calculations indicate that in a standard lake they can filter all the water in a lake in a 30 day period. So they take everything out of the water itself, all the food, etc. and put it down into the bottom. So it changes the ecology of the lake. It also has an effect of changing the chemistry of the lake. The water clarity has increased from a matter of, in the Great Lakes, has increased from a matter of inches to 30 to 40 feet because everything is drawn down and compacted into the benthic layer the of the lake which changes the ecology. The light penetration changes, the submerged aquatic vegetation where it was only in the old days only able to grow a few feet from shore now goes out, you know hundreds of yards from shore which changes the amount of oxygen produced by the during the day and the amount of oxygen used at night. So it really changes the conditions.

AJ: So not only changes the conditions. I imagine it also affects the native species as well.

Cameron: Yeah, it affects the native species in a couple of ways. First, since the ecology is changed certain species thrive and certain species have been impacted, when it comes to fish, species such as smallmouth bass which are site feeders they seem to thrive inlLakes where zebra mussels are present because they are better able to see what they’re fishing for. Species such as walleye, it’s kind of a wash. In some ways it is a benefit since they spawn on the bottom and the zebra mussels are filtering the water and keeping the water moving on the bottom. So their eggs have a better chance of producing young, they don’t become fungus, etc. However, since they are a nocturnal feeder they have to move further offshore in order to successfully feed.

Other species such as native mussels, it’s been a disaster for them. Since the zebra mussels, they’re the only species, the first species in the United States that has a byssuses where they can attach to other hard structures. They attach to the mussels and cause them to die over time. In fact in some water bodies, the number of native mussels have been reduced by about 98% from what they were prior to the zebra mussel invasion.

AJ: From an ecology perspective, is there anything that we can do to turn back the clock or to improve those conditions so that the native species don’t die out?

Cameron: Turning back the clock is difficult, if not impossible. Once an organism is there, it’s there for life. It’s much more difficult to remove biological pollution than it is to remove chemical pollution. There are people investigating the use of certain non-chemical agents in order to selectively kill zebra mussels in water bodies. The successes, it may be successful in certain applications. It’s much better to keep them from coming into a water body than it is to remove them once they get in.

AJ: We mentioned earlier how zebra mussels can affect many of our clients that require waterways to conduct daily operations. What are we doing to help them to control the zebra mussels once they’ve been introduced?

Cameron: Okay. There are a number of ways to control zebra mussels on infrastructure. There’s a unique solution for every facility. There’s basically a quiver of arrows that you can utilize to control the zebra mussels in a situation. That’s why it’s important to know a lot about the zebra mussel biology. It’s important to know a lot about the facility that you are looking to prevent zebra mussels from becoming a problem. And even within a particular facility, you have to look at various components that determine what the best way of mitigating the problem. Treating the problem at a hydroelectric facility is totally different than treating the problem at a drinking water facility and also from a lock and dam or whatever. So you really have to have a broad base knowledge of what the potential impacts are, the types of controls that you could utilize, and how to apply them in each situation.

AJ: So one of the things that I found most fascinating when we were working on the article was these big mats of mussels that you had shared images of with me. Can you talk a little bit about the mussel mats and how they can impact our clients?

Cameron: Sure. Again, as I mentioned, zebra mussels by themselves don’t look like much and basically why they cause impacts in this country is because there’s never been another species of organism in North America, prior to the introduction of the zebra mussel, that basically sticks on hard structures. The native mussels all bury themselves into mud, but the zebra mussel uses a byssuses, which is a thread like organ that that adheres to hard structures. So basically what happens is one zebra mussel will get into a facility and it will stick and grow, another one will stick and grow, another one will stick and grow, and pretty soon you have mats up to a meter thick of mussels in a facility if it’s not controlled. Now what happens is that the mussels on the inside, closest to the structure, will either get old and die or more likely won’t get sufficient oxygen or won’t get sufficient food and they will die and then for whatever reason once they’re dead the byssal structure is not attached to the shell, as a lot of people believe, but they’re attached to the soft tissue within the mussel. It becomes loose and this whole mat of mussels, called the druses, will ablate and rush further down into a system and generally the way most power stations and hydroelectric facilities and drinking water facilities are designed, there’s big pipes on the outside and the pipes keep getting smaller as you enter in the system. So you’ve got a big mat of mussels that gets drawn further into the system until it reaches a pipe or a structure where it can go no further and it basically shuts off the water flow to that particular system.

AJ: I’m sure it’s very, very damaging to operations.

Cameron: Very, very damaging may be an understatement. I mean the big concern early on is that a nuclear power facility has a rapid derate and not being able enough cooling water through their condensers and have to you know, go offline.

AJ: I remember you were talking to me when we were writing the article about, refresh my memory, I think it was a drinking water facility over Christmas.

Cameron: Yeah, it was one of the first facilities that were impacted by zebra mussels and basically now zebra mussels are better controlled because everybody’s aware of them and they don’t let the problem go too far down the road. Now this facility did not realize that there was an issue until they started not being able to draw sufficient water.

And I guess it was over Christmas time where they weren’t able to draw sufficient water. So the drinking water facility shut down. They had to run special water lines out into the lake in order to get sufficient water to service their customers. And beyond that because there are so many mussels in the system, they had to clean them out and when they cleaned them out all the big mussels that were in the system died and when organisms die they rot and they got into the system and caused a secondary shut down.

AJ: They really fascinate me. For being such an invasive species, I really enjoy learning about them while we were writing the article and as I mentioned earlier, they’re currently in the news. Can you tell us a little bit about the moss balls and the pet store recalls that have been covered by the local news and national news outlets?

Cameron: Yes about, I think it was three weeks ago, I was contacted by the state of Washington Non-indigenous Species Coordinator, in their fish and wildlife service, and was asked whether I could identify and verify that the organisms they photographed and sent to me were zebra mussels. And sure enough, they were zebra mussels, they weren’t really big but there were more than a few. And speaking with my contact out there. He said they were on these, they call them moss balls in the pet trade or they call them beta buddies in the pet trade and basically what they are is a species of algae that forms into these moss-like balls that they put into aquariums and they’re kind of interesting because at night they sit on the bottom, but during the day, once photosynthesis is involved, they release oxygen and it traps itself in the ball and they kind of float up and down in the aquarium and you know, they call them beta buddies because they put them in the Siamese fighting fish or beta tanks and as they go up and down they kind of look like a little volleyball that the Siamese fighting fish will play with. Now, unfortunately these beta balls or moss balls or beta buddies or whatever, they are imported from the Ukraine and other areas in the East where the zebra mussels are ubiquitous. So once they found these zebra mussels at this particular pet store, they took a look around and called this pet chain, which is a major pet chain and found that in the two weeks prior to that, they imported over a hundred thousand of these individual beta balls, which they distributed in 49 of the 50 states.

AJ: Wow

Cameron: Taking a look at doing the sampling of the beta balls. They found a good proportion of them actually head zebra mussels and I believe they have found zebra mussels in at least 20 of the states where they have looked. Now, let me say that the pet stores were good stewards and immediately pulled them off the shelves and destroyed them in a manner that the fish and wildlife wanted them to so there’s they’re no longer being distributed, which is great. The big concern are the ones that were released and sold to the individual pet owners prior to that recall because they have no way of tracking who’s got them. Although they released a lot of news and there’s a lot of publicity out there where they have asked the pet owners to properly destroy them and giving them methods to destroy these moss balls so they won’t be introduced to the environment. There’s a concern that there have been more than a few that have been released. People say well, how would they get in the environment? Well there’s a lot of young kids that don’t want to, for lack of a better term, to flush their pets down the toilet to get rid of them or whatever, so dad takes them out and puts them in a little local pond at the local river and watches them swim away all happy and makes the child feel real well. But unfortunately it’s a vector that’s been proven to distribute organisms in the pet trade environment causing issues. There are goldfish and just about every water body where you want to look. The goldfish are pretty interesting because they grow about six inches long, but their tails and fins stay about the size of a goldfish in a pond. So they look like these big gold bubbles. That’s kind of innocuous. But the Burmese pythons in the Everglades were released as a part of the pet trade are causing all sorts of problems. There’s a species of fish called the snakehead in the Mid-Atlantic States that was introduced via the pet trade. They’re pretty interesting because when they’re longer about pencil-sized they have these really nice stripes, but they eat everything else in the tank and they’re soon about, they’re quickly about two feet long, they lose their stripes, they’re not real pretty anymore, so people dump them into the local environment where they continue eating and destroying the environment.

AJ: And they probably don’t realize that that is going to happen.

Cameron: Oh, exactly. I mean, I probably did it as a youth and probably everybody else has released something as a youth because they want to free the animal back into the environment.

AJ: Can you tell me a little bit more about how the release of the moss balls could potentially infect these environments and why people should reconsider what they are doing when they release the moss balls into these waterways?

Cameron: Yes. Well, even in the Northeast where zebra mussels have been around for a long, long time. There are a lot of reservoirs, lakes, etc. where zebra mussels have not been found before. Now, some of them are self-protecting due to the water quality issues I talked about before, but some they just haven’t had them introduced at the right time or the right numbers into that particular water body for them to cause a problem. In fact, Hagerstown Lake, it was just brought to my attention that they just found zebra mussels there for the first time over the past couple of weeks and that’s a major reservoir in Pennsylvania that is surrounded by other waterways that are heavily infested with zebra mussels, but they’re not there yet. Now with the people releasing them, there’s no predictability where a person is going to release these beta buddy moss balls. So, they may very well go into a water body that has not had an introduction before. Now, the problem with these moss balls is that they’re usually not just one or two zebra mussels on them. When they’re finding these moss balls there’s tens if not, you know 50 zebra mussels on the moss ball. So when they’re released there’s a lot of potential for them to become established in the water body.

AJ: So basically what you’re saying then is that we’re introducing these moss balls which are releasing the zebra mussel veligers into these virgin waters and industry that relies on those waterways whom have never had to think of how to mitigate zebra mussels to conduct daily operations, now need to start considering it.

Cameron: That’s correct. And it’s important to note that if there’s a potential for the zebra mussels to be introduced to the waterway. It’s important for the water users to come up with a methodology to control them, revisit what potential controls they might have to utilize and make sure that they’re monitoring for the mussels and to see whether they in fact have become established in that particular water way because it’s much easier to control them as they become a problem than after they become a problem.

AJ: Cam, thank you for being on this episode of CEC chats.

Cameron: Thanks for having me AJ.

AJ: For more information on this fascinating subject making its way into the national news visit cecinc.com/blog. Thank you for listening.

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