It was originally believed that the fish needed very specific breeding conditions, requiring long rivers to spawn, so some scientists believed the infestation would be reduced. It turns out the fish is less picky about its spawning habitat.
One of the Asian Carps, the Silver Carp, has also been found to eat an algae very common to the Great Lakes, cladophora. It's a native food source that could be stripped from the food chain, just like the small diporeia shrimp.
New evidence indicates silver carp, one of the most common Asian carp in Illinois, can eat cladophora, an algae species prevalent in the Great Lakes. Previous studies had concluded that for Asian carp to survive, they need plankton, which are scarce in the southern end of Lake Michigan.
Evidence is also mounting that Asian carp don't need to travel up long rivers to spawn, which would increase the number of potential breeding areas around the Great Lakes, Carl said. Scientists previously thought rivers of at least 62 miles (100 kilometers) were necessary for carp larvae to develop before eventually moving into a lake.