Focus on Aquatic Invasive Species – What are Asian Carp?
Posted: March 20, 2017
Clockwise: Bighead carp, Courtesy of US Fish & Wildlife Service, Michigan Sea Grant, Bugwood.org; Grass carp Pam Fuller, US Geological Survey, Bugwood.org; Silver Carp, US Geological Survey, US Geological Survey, Bugwood.org; Black carp, Rob Cosgriff,
Asian carp are voracious filter feeders that were imported in the 1970s to filter pond water in Arkansas fish farms. They were able to escape because of flooding and establish breeding populations in the Mississippi basin.
Their numbers have grown so that Asian carp represent over 97% of the biomass in portions of the Illinois and Mississippi Rivers.
Voracious filter feeders, bighead (Hypophthalmichthys nobilis) and silver, (Hypophthalmichthys molitrix) carp consume up to 20% of their body weight per day in plankton (small floating plants and animals vital to the food chain). Black carp (Mylopharyngodon piceus) consume mussels and snails, while the vegetarian grass carp (Ctenopharyngodon idella) eat massive amounts of aquatic vegetation (up to 40% of their weight per day), removing both food and shelter necessary for native fish. These fish are quite large, with bighead and grass carp growing to 100 pounds or more; silver and black carp grow to 60-70 pounds. The large, hard-headed silver carp can leap up to 10 feet out of the water when startled by boat engines, often colliding with people and causing injuries. https://www.youtube.com/watch?v=rPeg1tbBt0A
Efforts to prevent Asian carp from entering the Great Lakes are ongoing because once established in an ecosystem they are virtually impossible to eradicate. No natural predators take adult carp and females lay approximately half a million eggs each time they spawn.
Temperatures in the Great Lakes are well within those in the fishes’ native range, and nutrient-rich bays, tributaries and other near-shore areas offer Asian carp an abundant supply of plankton. Plankton is eaten by most young and many adult native fishes as well as native mussels and the voracious carp are expected to strip the food web of this resource. There is also a great deal of spawning habitat in the U.S. portion of the Great Lakes suitable for Asian carp.
The Chicago Area Waterways System, a series of sewage and shipping canals, is the most vulnerable pathway for Asian carp invasion of the Great Lakes. The U.S. Army Corps of Engineers maintains electric barriers across the Chicago Sanitary and Ship Canal to stop these invaders from entering the Great Lakes. This barrier creates a strong electrical field across the canal to deter the carp from moving upriver. Asian carp may also be spread through release of bait fish or fish sold live for food, and would do quite well in Pennsylvania rivers.
It is unlawful in Pennsylvania to possess, sell or purchase live silver, bighead or black carp or introduce or import these species into Pennsylvania waters. Sterile grass carp can be stocked, but only with a permit.
To avoid spreading invasive species, never release plants, fish, or animals into a body of water unless they came from that body of water.
For more information, visit:
Pennsylvania Sea Grant https://seagrant.psu.edu/resource/aquatic-invasive-species-invasive-species/asian-carp