Thank you very much.
I do have a deck and if you turn to the second slide, it is a quick overview on risk assessment for aquatic invasive species. The first step is to look at the probability that a species will be introduced, taking into account the likelihood that it will arrive, survive, establish, and spread. The second part of a risk assessment is to determine what the magnitude of the consequences would be if the species was successfully introduced. Combining these two parts gives you the ecological risk of that species to the ecosystem.
Turning to the next slide, the risk assessment for the bighead and silver carp was drafted by experts from DFO, the U.S. Geological Survey, and the Great Lakes Fisheries Commission. This draft was presented at a meeting of invited binational experts and freshwater fish invasive species experts in risk assessment, or experts in invasive species modelling.
The peer review meeting followed a rigorous review process for science advice set by DFO, which follows the science advice for government effectiveness principles. Proceedings and a science advisory report have been completed, which have resulted in strong, transparent, and scientifically defensible products, including an actual risk assessment authored by me, Dr. Mandrak, and our American colleagues.
I will discuss some of the key results for each stage of the risk assessment process.
Two categories of potential entry routes were identified and assessed: physical connections and human-mediated release. The most likely entry point to the Great Lakes is through an existing physical connection with an already invaded water body, specifically the Chicago Area Waterway System, CAWS, into Lake Michigan. I wish to note that the CAWS is a variety of water connections, not just the Chicago Sanitary and Ship Canal. Other physical connections exist but were assessed to be at lower risk. Trade had a greater uncertainty for our assessment, and more information would be required in order to provide an assessment with greater certainty.
We found as a key result for survival that enough food and habitat exists throughout all five of the Great Lakes, especially Lake Erie, for these fish to survive and overwinter. These species are opportunistic feeders. They consume a wide range of food sources, including bottom debris and pseudofeces from zebra mussels in order to survive. Pseudofeces is the biological waste product from zebra mussels.
The key result for establishment is that Asian carp require rivers for spawning, and we found that suitable spawning conditions exist in at least 49 Canadian rivers. Extensive wetlands are available throughout the Great Lakes and these provide an excellent nursery habitat for young Asian carp. We also found that positive population growth would occur in the Great Lakes, and that it would require as few as 10 adult females and a similar number of males to have a greater than 50% chance of annual successful spawning. This requires the fish to be able to find each other in suitable spawning habitats, but because they are drawn to rivers for spawning, we think this would occur.
I will now turn to the key results for spread. Following introduction into a single lake, these species would be expected to spread to the other lakes within 20 years. The spread would be more rapid for lakes Michigan, Huron, and Erie, and potentially Lake Superior. Spread into Lake Ontario would be longer as Lake Erie is extremely suitable and these species would be less inclined to leave that lake.
I will now turn to the key results for consequences. Plankton-eating fish, plankton being the very small plants and animals in the water column, fish such as gizzard shad and buffalos, would be forced to compete for their primary food source. Bighead carp have very specialized adaptations for very effective consumption of plankton. They have a voracious appetite. They consume up to 40% of their body weight daily. This will significantly reduce the number of native fish in the Great Lakes region, and will have an impact on this delicate and important part of the food web. In turn, the reduction of these native fish would reduce the number of predatory fish such as yellow perch and walleye.
Turning to the key results for our overall risk, if no additional action is taken, the overall ecological risk of bighead carp to the Great Lakes is high, especially to the central lakes, those being lakes Huron, Michigan, and Erie. The impacts will increase over time.
The magnitude of impact of bighead carp in the Great Lakes is directly related to their becoming established. Therefore, preventing establishment is critical.
For Canada, where there are no established Asian carp, our focus would be on preventing introduction. This is the main driver of the new Asian carp program that Mr. Burden spoke of.
I would be happy to take any questions.