Thank you very much.
Bonjour, mesdames et messieurs. Thank you very much for inviting me here. It's certainly a pleasure and an honour to be here to talk to you today.
My name is Istvan Imre. I am a biology faculty member in the biology department at Algoma University, which is Ontario's newest university. It's the smallest but arguably probably the most formidable, as you will see.
Today we'll be talking to you about sea lamprey. I am not an expert on the five species of Asian carp or the northern snakehead, and arguably the sea lamprey are a clear and present danger. They are right here, right now. Out of the close to 200 aquatic species that we know have infested the Great Lakes in the last decade or so, without a doubt sea lamprey is the most formidable. Also, as you are probably aware, it takes the most effort and the most amount of money to try to control it.
You might be looking at my title and thinking, “Oh, he's a sensationalist”. That's partly true, because I like Schwarzenegger and the whole Terminator series, but if you look at the mouth of the sea lamprey that you see on the screen, you will probably understand that for a lake trout, or for other fish species found in the Great Lakes, an organism attaching to them with that kind of formidable armament really will result in termination of that individual.
Very briefly, I will talk to you about the taxonomy and the life cycle of the sea lamprey and its invasion history, or how it got here. I will also say a couple of words about the Great Lakes Fishery Commission, because I understand that you will be thinking about renewing that convention between the U.S.A. and Canada, as well as a couple of words about present control measures of sea lamprey and also a couple of proposed measures.
The reference at the bottom of the screen is to one of the papers that I wrote. Most of the information that we'll be talking about today is found in that publication.
First, although most of us think of the sea lamprey as an eel, it really is not an eel. In fact, it's a fish species that is a lot more ancient than that, although I know it looks very similar. In fact, it's jawless, hence the name “agnatha”, which means jawless. It is also grouped into a group called cyclostome, which means “round mouth”, for obvious reasons. It is actually native to the Atlantic Ocean and invasive in the Great Lakes ecosystem.
It has been around much, much longer than the dinosaurs. Why do I mention that? Just so we understand that this fish, from an evolutionary standpoint, is a really successful species. As such, it might be quite difficult to exterminate.
Now, sea lamprey is not the only species we know of. There are about 40 species of lampreys. Many of them are parasitic, but only the sea lamprey has gained the notoriety that we know of in the last century or so.
It's an anadromous fish, meaning either that it lives in the Atlantic Ocean and goes into the Atlantic Ocean shoreline tributaries to spawn or, if it's land-locked, that it lives in the Great Lakes ecosystem and then goes to spawn into freshwater tributaries. The adults are at the parasitic life stage.
As you can see from the pictures, they have horny teeth-like structures in an oral hood that is used to attach to the side of the fish. They use their tongues to rasp a hole in the side of the fish. You can see in the pictures what is the very unfortunate outcome of a sea lamprey attack, as well as, in the upper right corner of the picture, a lake trout with two individuals attached to it.
Another picture shows that lake trout. It's not just the attack that causes the death of the fish, but often.... Actually, all small fish die from it. Some large fish might survive the actual attack, but they succumb later on to various bacterial infections. About 40% to 60% of lake trout die once they have been attacked by sea lamprey.
To give you a bit of applied data in terms of what is the significance in terms of economic injury, a sea lamprey can kill 40 or more pounds of fish during its adult life stage. We know of instances when only one of every seven fish attacked actually survived. Even though we tend to think of sea lamprey as preying on salmonids, which would be salmon-like fishes and trout and salmon, they actually prey on a broad variety of native fish species that live in the Great Lakes ecosystem, including whitefish, burbot, walleye, and even lake sturgeon—so they are really indiscriminate parasites.
My illustration shows the life cycle in a nutshell. The reason for me presenting this is so that the committee understands that many actual geographical areas or habitats that the sea lamprey needs for its life cycle overlap with those of other fish species, thereby making separate control of that species quite difficult at times.
The spawning phase happens from late April to June, depending on the water body. These fish need very clean habitat, clean streams, not unlike salmon. That is ironically one of the reasons why, when we cleaned up St. Marys River over the past couple of decades, with the habitat improvement the sea lamprey managed to move in there and spawn.
Once the eggs are deposited the adults die. The larvae are filter-feeders for anywhere from three to about 17 years. They reside in streams. After that they metamorphose and go into the nearest large lake or the Atlantic Ocean and become parasitic. They live in that life stage for about 12 to 20 months. Then they reproduce and the whole cycle starts all over again.
On the invasion history, we know that sea lamprey have been present in Lake Ontario since 1835. Their landlocked populations have been known to occur in streams around Lake Ontario, but we don't have any data about sea lamprey in the other Great Lakes before 1921. All of us know that the Welland Canal was built in 1829 to connect Lake Ontario and Lake Erie. That indirectly opened an avenue for the sea lamprey to infest or invade the other Great Lakes.
We found sea lamprey in Lake Erie in 1921, and from there on it spread very quickly into the other Great Lakes. By some accounts they had already finished their invasion by 1939. They were also present in Lake Superior. In a very short time, one or two decades, the population exploded, resulting in a quite precipitous decline in both recreational and commercially important native fish species populations.
Why was there this sudden explosion? These species are brand-new to this ecosystem, meaning that the native fish species did not co-evolve with them. They did not recognize them as a predator, or didn't evolve proper defence mechanisms against them, so they could do a huge amount of damage in a relatively short amount of time.
As an example, before the sea lamprey entered Lake Huron and Lake Superior, Canada and the United States could harvest about 15 million pounds of lake trout. Once the sea lamprey got in, by the early 1960s the catch was down to about 300,000 pounds. So there was about a 50-times decrease from previous catch levels. That of course resulted in the collapse of a number of commercial fisheries.
To give a quick idea for the committee of where the sea lamprey is present around the North American continent, the area shown in brown is where the sea lamprey is native, along the U.S. and Canadian eastern seaboard. The area shown in red is where it has become invasive in the last century or so.
As we all know, the Great Lakes Fishery Commission was put in place in 1955-56. One of the major responsibilities of the commission was to implement a program to try to manage this formidable invasive pest. Presently the program is composed of a multi-pronged approach using chemicals like lampricides to kill off the juveniles that reside in streams. We trap the adults, sterilize the males, and release them back to compete with healthy males. We also have a so-called barrier program on 50 or so tributaries around the Great Lakes to stop them from accessing their spawning areas. Obviously, if you have a barrier that stops the sea lamprey from going to their spawning stream you don't have to treat that habitat with chemicals.
We started working on the lampricides in the early 1950s. Scientists believe they have now tested some 6,000 compounds. In 1958 we found one that was very effective, popularly known as TMF. It is applied to streams in industrial quantities. It's very effective in killing larvae at their filter-feeding stage. We were able to reduce sea lamprey populations by about 90% in the 1960s.
However, we all know that pesticides have a negative connotation. They're becoming more and more expensive. So the fishery commission put an emphasis on coming up with other ways of controlling this pest.
We can also trap them. This would be a small portable trap on smaller streams. These can be quite effective in catching the adults when they are migrating to their spawning grounds.
When we are incorporating traps into larger barriers, they tend to have a lot lower efficiency. A large amount of research at the present time is aimed at trying to come up with ways of making these traps more effective with newer designs.
The sterile male release program, as you probably know, has been recently stopped. This involved using nasty chemicals to basically sterilize males by chemical means and releasing them into their habitat to compete with healthy males. Of course the eggs of females that were fertilized by these males did not survive.
Finally, the barrier program I mentioned is composed of several different barrier types, including low-head barriers, which we will be showing examples of, as well as electric barriers, raised crest barriers, and velocity barriers. All of these are aimed at trying to take advantage of the lesser swimming ability of the sea lamprey and protecting habitats above the barriers from species spawning in those areas.
Just to give you an idea, these are the locations of barrier dams around the Great Lakes. There are over 50 of them at the present time. To put it in context, we have about 5,800 streams around the Great Lakes, so it's a very small number of streams that actually have this control device on them.
This is what a barrier dam would look like. It's about 1.5 metres to 2 metres in height. Sea lamprey cannot cross it, but several other fish species can. You can see a large salmonid in the air that was able to jump and swim over it. Nevertheless, there is information telling us that it still disrupts the migration of several other fish species that are native to the Great Lakes ecosystem.
This would be an example of an inflatable barrier. This is being raised up only during the migration season and then being lowered after the sea lamprey migration season to allow for the movement of other fish.
The Great Lakes Fishery Commission has put a lot of emphasis on trying to decrease reliance on chemicals like the TFM, and coming up with more improved use of traps and barriers, other more environmentally friendly choices, as well as new alternate control methods.
I'll be finishing in about two minutes. Sorry for being a bit over time.
One new measure that has enjoyed quite a bit of research attention over the past five to ten years is the use of pheromones, which are substances that typically attract individuals to the point of origin. Larvae have a so-called migratory pheromone that is used by adults. It's considered by adults as a kind of habitat reliability index; if there's a pheromone coming out, that means there are live larvae so it's a good spawning habitat.
Males also release a sex pheromone to attract the females during the spawning phase. Scientists have been able to synthesize these chemicals to try to attract lamprey to traps and of course kill them.
An approach I have championed, so to speak, over the past couple of years—I finally got a bit of money from the fishery commission—is to ring the alarm. As opposed to attracting them, it's about scaring them away. That's by using natural alarm cues--for example, chemicals that might reside in their skin or internal organs or in the decaying sea lamprey. Or we could use direct predator cues. These would be urine, saliva, or other chemicals originating from known sea lamprey predators. This research is ongoing.
How could we use that? Obviously if it works, we could prevent sea lamprey from entering certain streams and concentrate them into streams where we already have trapping or other control methods. Or during the day, when they typically hide under rocks and under cut banks, we could perhaps scare them out from hiding and make them more available to trapping devices.
It's nothing new. It has been used. It's a push-pull strategy, namely pulling them with pheromones and pushing them with repellents. It has been used with inside pests, and we are trying to use the same approach towards sea lamprey.
Thank you very much for your attention. This is what I wanted to talk about. The reason for going into this kind of detail is to make you realize we have to look at every life stage where we can potentially control the sea lamprey. As you see, the Great Lakes Fishery Commission is already using a multi-pronged approach, to try to control them in any way and by any means possible.
So far, we have been pretty successful, with the exception of the St. Marys River. That is probably the hot spot of the Great Lakes, and this is where my university is, on the shore of St. Marys. That one river system is actually seeding most of northern Lake Huron with sea lamprey. Further research is still desperately needed.
Thank you.