Indiana Ag Connection - Asian Carp Survive in Larger Lake Michigan Area than Thought

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Asian Carp Survive in Larger Lake Michigan Area than Thought
Indiana Ag Connection - 08/14/2019

Asian carp are capable of surviving and growing in much larger portions of Lake Michigan than scientists previously believed and present a high risk of becoming established, according to a new modeling study from University of Michigan researchers and their colleagues.

Some previous studies suggested that low food levels in Lake Michigan could be a barrier to the establishment of bighead and silver carp, which typically feed on algae and other types of plankton. Bighead and silver carp are the two Asian carp species of greatest concern for the Great Lakes.

But earlier studies did not consider the fact that bighead and silver carp are opportunistic feeders capable of surviving on a wide variety of diets, including dead organic matter called detritus. In Lake Michigan, detritus includes bits of resuspended fecal pellets from countless quagga and zebra mussels on the lake bottom.

In addition, previous studies did not evaluate potential carp habitat more than a meter below the lake's surface.

When diet flexibility and subsurface habitat were factored in, the amount of suitable Asian carp habitat in Lake Michigan increased dramatically, according to study lead author Peter Alsip, who conducted the research for his master's thesis at U-M's School for Environment and Sustainability.

At certain times of year, the model showed that the entire extent of Lake Michigan, which has a surface area of more than 22,000 square miles and an average depth of 280 feet, contains suitable bighead carp habitat somewhere in the water column, according to Alsip, who now works at the U-M-based Cooperative Institute for Great Lakes Research.

Silver carp habitat was confined to nearshore, nutrient-rich areas. The study was published online Aug. 12 in the journal Freshwater Biology.

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