Asian Carp

File:Hypophthalmichthys molitrix adult.jpg

Though all four of the species listed in this question are invasive Asian carp, the silver carp, pictured above, is the species with the nasty habit of jumping from the water when startled. Both it and it's close relative, the bighead carp, are extremely harmful invasive species that were brought to the United States in the early 1970s to control algae and plankton at fish farms and water treatment facilities. They soon escaped into the Mississippi River Basin and have since spread throughout the Mississippi, Missouri, Illinois, and Ohio Rivers and their tributaries (See USGS Distribution Map). They are currently a threat to enter the Great Lakes by means of the Chicago Sanitary and Fish Canal.

Asian carp cause immense problems for native fish and other aquatic animals because they lower water quality, outcompete native species for habitat, and consume huge amounts of algae and zooplankton, which devastates the food chain. Both silver and bighead carp can quickly reach high population densities and dominate an entire river system. In fact, they currently make up 90% of the biomass in some stretches of the Illinois River and Mississippi Rivers!

Asian carp reach a large size (up to 100 lbs.) and are edible, yet it is unlikely that they will become an important species to sport fisherman because they are "filter feeders" that strain their food from the water. Therefore, these fish are difficult to catch on a hook and line. They are often taken by snagging or through bowfishing, however. They are currently being fished commercially, and markets for them are being sought. However, it seems unlikely that enough can be harvested to control the population.

Though "no established populations" of silver or bighead carp are known to exist in Minnesota, individual fish have been caught by Minnesota commercial fishermen in both the Mississippi and St. Croix Rivers (Minnesota DNR, 2014). Similarly, individual grass carp have been taken in Minnesota border waters. Black carp have not yet been found in Minnesota rivers or lakes. One can only hope that efforts to prevent these species from becoming established in Minnesota waters are successful.

           

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Photo from Wikimedia Commons