Thank you. It's a huge issue. Some of these species we're dealing with are from the Black Sea basin. You hear the word “sea”, and you say, why are marine species coming into the Great Lakes? They're not strictly marine species. They live in coastal areas, in river outflows in the Black Sea—things like the zebra mussel and the round goby, etc.
They've come over largely because they built these canals throughout Europe that allow them to get into what we consider to be hot ports, such as like Rotterdam, Antwerp—freshwater ports. Once they're in those ports the ships bring them to the Great Lakes. Otherwise they could never get here.
Once they're here, a whole host of other human mechanisms allow them to spread from the Great Lakes to our inland lakes. The three worst cases we're dealing with currently are zebra mussels, quagga mussels—they look identical, although they are distinct—and the spiny water flea.
The spiny water flea is an organism with the total length of maybe half an inch. As the name suggests, it's a small organism with a long spiny tail. The tail prevents small fish from feeding on them. This species has now spread to at least 160 lakes that we're aware of in Ontario. It just spread last year into Manitoba. If we want to preserve Canadian biodiversity in our lakes, this is precisely the type of species we want to keep out.
My colleague Dr. Norman Yan at York University, has demonstrated conclusively that as the species invades new lakes—it's a predator and it preys on the native plankton—on average it will drive three native species to extinction in those lakes. This has happened at least 160 times that we're aware of, where it has been reported. We're losing lots of populations of native species due to the spread of this water flea.
The way it's spreading is that people go out with a downrigger line, say out on Lake Ontario or Lake Erie or Lake Huron, whatever the case may be. It's in all of the Great Lakes. If I go trawling through the water for salmon, I have that line down. If you think of that, how often would a person pull up their downrigger line? It's not very often. As the boat is moving, that vertical line is sampling an enormous volume of water, because it's cutting through the water.
These animals are small but they have this big tail, and they can't get out of the way as the fishing line comes by. The fishing line grabs the animal by the tail, and they move down the fishing line until they reach a rough spot. They will form a bolus or a knot at that rough spot. The angler finds out they have a problem when they try to retrieve the line. They reel the line in, and all of a sudden it stops. It stops because you have this knot on the line, and the knot might be comprised of, say, 500 individual fleas.
Many of these species can reproduce either sexually or asexually. The asexual ones are the problems. These females can produce eggs that are just like apple seeds. If she happens to have some of these apple seeds in her brood chamber where she holds the seeds and you take this bolus out of the water on the fishing line, all the animals on that line die immediately. But if the females are carrying eggs, the eggs are desiccation resistant. If you view them as apple seeds, they can go through a duck's or a fish's stomach.
If that angler then goes to another lake, maybe three weeks later, and doesn't clean the fishing line off first and then uses the fishing line, this crust falls off into the water. The eggs suddenly detect they're being hydrated, start hatching, and you get new populations. It has spread throughout Muskoka. It's on the border of Quebec—it may well be into Quebec by now—and we know it just invaded Manitoba.
The zebra and quagga mussels are far more famous. Most people know about the zebra mussel, but the bigger problem is the quagga mussel. They will adhere to any solid surface on the exterior of a boat. They could be on the motor or inside the motor.
If people trailer their boats that have these animals attached to them.... In many cases the animals grow on aquatic plants in coastal areas of lakes and the plants break off and get stranded around the marinas. You back your trailer down to pull your boat out and the trailer gets a lot of these aquatic plants attached to it. If you don't clean the trailer off and you go to another lake, not only might you introduce the plant, but you're going to introduce all the zebra and quagga mussels that are living on the plant.