Sure. The reality of these fish is I think amply illustrated by what's happened in the Mississippi drainage. As I understand it, nine of ten fish found in stretches where they are found are Asian carp, and the native species that used to be there are gone. They don't exist anymore.
Their limiting factors are three, essentially. One is the availability of a food source. They're filter feeders. They require planktonic food. They effectively feed the same way that a great blue whale does. They swim around with their mouths wide open and they eat things. They eat anything that gets in their mouths. They eat vegetable matter, so small algae, they eat plankton, they eat larval fish, they eat floating eggs—they eat all of it.
In that respect they may find themselves in competition with the zebra and quagga mussels in some of the Great Lakes. But in places like Saginaw Bay, which is one of the major producers of walleye and perch—and historically, when there were a lot of herring, herring as well in Lake Huron. But the western basin of Lake Erie, which is the nursery, the factory of fish in Lake Erie, would be perfect for them in that regard. There is lots of all of that, in particular in Lake Erie. But you can think of similar habitats all over the Great Lakes where they would do well.
The second limiting factor is temperature. These things, if they get into Canadian waters, could exist all the way to 60 degrees north. They're an Asian species that have adapted to temperate and subtropical conditions. There is an assumption on the part of a lot of people that they require warm water. They do not.
In the third instance, they need rivers of indeterminate length but sufficient continuous flow over a sufficient distance to keep their eggs suspended. So depending on the temperature, that can be 80 kilometres to 120 kilometres, which is what I'm told, although the evidence from Asia suggests that they exist in systems where they don't have that, so clearly that's not a hard and fast rule. We don't know what they'd actually require.
One of the reasons Lake Erie is one of the really serious areas of concern is that all of that exists in the western basin of Lake Erie, without a doubt. The Maumee River, and potentially the St. Clair River and Detroit River systems, all have sufficient length, they have sufficient productivity, the temperatures are optimal, and they will do well there and they will knock out our fishery if they get in.