A study by researchers at the University of Michigan says Asian carp would do very well if they get into Lake Michigan, even in the deeper waters were food is less plentiful for big fish.
The study indicates that Asian carp would survive and grow in larger areas of the lake, and that would improve their chances of spreading to other lakes.
Asian carp are now the primary fish in the Illinois River, which leads to the Chicago Area Waterway System, and flows into Lake Michigan.
Asian carp were brought in to gobble algae in the South in the 1960’s, but they got into the Mississippi and now are in many tributaries.
The U of M study says lab experiments show that Asian carp can survive feeding only on zebra mussel waste deposits.
The study, published in the journal ‘Freshwater Biology,’ also found:
- Allowing the fish to feed on the broadest possible diet (phytoplankton, zooplankton and detritus) throughout the water column resulted in suitable habitat volumes that were 4.6 times greater than the narrowest diet (phytoplankton only) for bighead carp and 2.3 times greater for silver carp.
- While the extent of high-quality Asian carp habitat across Lake Michigan is relatively small, the risk of localized establishment events is high near river mouths and in nutrient-rich parts of Green Bay. The team’s model found suitable year-round habitat (which other models suggest is capable of supporting spawning and egg development) near the mouths of several rivers, including the Milwaukee and St. Joseph.
- Maps generated by the team’s model identified Asian carp establishment hot spots and the potential for cross-lake migration corridors “that may facilitate and accelerate lake-wide movements,” the authors wrote. Those maps could aid surveillance efforts by identifying areas to which bighead and silver carp might spread upon entering the lake.
- The relatively plankton-rich “deep chlorophyll layer” that forms each summer in offshore Lake Michigan waters is capable of supporting bighead carp growth. Previous carp studies did not evaluate growth potential in this layer, which forms at an average depth of about 100 feet.