Grass Carp
Scientific Name:
Ctenopharyngodon idella
Type:
Fish
Habitat:
Lakes, ponds, and rivers
Range:
Native to eastern Asia, China, and Russia; introduced to the United States and have been reported in 45 states across the U.S.
Status:
Least Concern (IUCN Red List)
This species is
INVASIVE
to the Truckee Meadows.
Identification:
Grass carp (also called the white amur) are a species of freshwater fish that has been introduced into many areas to serve as a control for aquatic weeds and plants. These carp are mostly silver and can be different shades of light green, white, or brass. The grass carp has a short face with a small mouth, and two rows of teeth. These fish can have a lifespan of 5 to 20 years depending on their environment and local predators. On average, a mature grass carp can weigh 10 to 20 pounds and grow several feet long, but some grass carp have been reported to be over 6 feet long and weigh nearly 100 pounds! Grass carp feed on a wide variety of underwater vegetation, making them ideal for weed control.
Fast Facts:
In some areas these fish are regulated and must be bred to be sterile (called triploid). This makes them great for controlling underwater weeds because they cannot reproduce and negatively affect the ecosystem after their job is done.
In other areas the grass carp have not been regulated or made to be sterile and can reproduce (called diploid). They pose a threat overeating underwater vegetation and throwing the ecosystem out of balance.
These fish can live anywhere where there is a consistent supply of freshwater plants to eat. In the wild, grass carp only spawn in moving water, where they let their eggs drift downstream with the current.
Grass carp pose a problem to some areas. They eat too much vegetation, taking food and habitat away from other fish and making it easier for other plants to take over and grow out of balance. Grass carp also make water clarity worse in places where they have been introduced.
Sources:
U.S. Fish and Wildlife Service, Grass Carp (Ctenopharyngodon idella var. diploid), 2020, https://www.fws.gov/fisheries/ans/erss/highrisk/ERSS-Ctenopharyngodon-i della-final.pdf
USDA, Grass Carp, 2021, https://www.invasivespeciesinfo.gov/aquatic/fish-and-other-vertebrates/gra ss-carp
USGS, Nonindigenous Aquatic Species - Grass Carp, 2020, https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=514
Image: Asian Carp Regional Coordinating Committee, https://www.flickr.com/photos/acrcc/37814721245, license https://creativecommons.org/licenses/by/2.0/, cropped from original.
Contributor(s):
Kevin Livingstone (research & content)
Alex Shahbazi (edits & page design)