Thursday, September 9, 2010

Why Worry About Asian Carp When There Are Quagga?

Dr. Charles Kerfoot, a researcher funded by NOAA and The National Science Foundation, isn't worried about Asian Carp. He says "by the time the carp get here, there won’t be anything left for them to eat," referring to the quagga activity that has been identified in Southern Lake Michigan.

These small European mollusks, about the size of a lima bean, have been discovered in abundance feeding on phytoplankton in Lake Michigan. A doughnut shaped collection of algae and other tiny plants was discovered in winter with the aid of NASA’s new Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Between 10,000 and 15,000 quagga mussels can inhabit one square meter in the soft lake bed and have been found in all of the Great Lakes. Consuming phytoplankton at a rate of five to seven times that of the production rate, the massive number of quagge are excreting enough to stimulate the growth of Cladophora algae (see the DNR article on it here). When the algae dies and decomposes, it eliminates oxygen from the surrounding waters increasing the likelihood of botulism. The predictable result from all this is a decline in lake species starting with smaller ones such as zooplankton, and then continuing on to chub and alewives, eventually leading to even the larger fish that inhabit Lake Michigan.

The Journal of Great Lakes Research has published the article on Kerfoot's research called "Approaching Storm: Disappearing Winter Bloom in Lake Michigan," which is available online, here. For an overview of the topic see the Michigan Tech News release, here.

Video of quagga mussels feeding by John Karl at UW Sea Grant.