Scientific Name: Ctenopharyngodon idella
Common Name(s): Grass Carp, Amur Carp

Identification:

Grass carp are one of the largest fish species in the minnow family, Cyprinidae. Cyprinidae is the most diverse family of fish, with around 1300 living species described today, and 60 of those species can be found in Arkansas. Mature grass carp adults can weigh between 65 and 80 pounds in their native habitat and have been found to get up to 50 inches in length. They have a broad and blunt scaleless head with a downward pointed mouth (subterminal to terminal), and no barbels (fleshy, whisker-like structures around mouth). Their body is elongated, with large scales that form an ombre pattern from tan or olive on their top (dorsal) scales to silver on their bottom (ventral) scales. The large dorsal scales have dark edges that create a crisscross pattern along their body. They have a forked tail (caudal) fin and 8 to 9 dorsal fin rays. They have a prominent and decurved lateral line 37 to 47 scales in length.

Interestingly, the world record grass carp caught was caught in Bulgaria in 2009 weighing 87 pounds 10 ounces.  The Arkansas record was caught at Lake Wedington, near Fayetteville, in 2007 and was certified at 80 pounds by the Arkansas Game and Fish Commission.

(Cudmore & Mandrake 2004 , United States Geological Survey)

Range:

Grass carp are native to Eastern Asia but have been stocked in the United States since the mid-1960s. Some of the first grass carp were imported to Stuttgart, Arkansas, and raised at the United States Fish and Wildlife Service Fish Farming Experimental Station. The first recorded stocking of grass carp occurred in Lake Greenlee near Brinkley in 1968. Grass carp were established in the Lower White River below Stuttgart by the 1970s.  Grass carp are currently found in 45 states, with no observation of grass carp in Alaska, Maine, Montana, Rhode Island, or Vermont.

Ecology:

Grass carp are large herbivorous fish from Eastern Asia, where they prefer the slow-flowing backwaters of large rivers as well as still lakes and ponds. Their diet is primarily composed of aquatic plants. They live in environments with temperatures from 32 to 100 °F. They reproduce in temperatures between 65 and 85 °F in riverine environments with large volumes of turbulent and flowing water. Grass carp are broadcast spawners. Females lay copious amounts of eggs in free-flowing waters fertilized by males. The eggs remain suspended in flowing water until they hatch.

History in Arkansas:

In the early 1960s, the U.S. government aimed to find a way to use biological controls in lieu of chemical herbicides to control aquatic nuisance vegetation in natural river and lake ecosystems along with aquaculture facilities and sewage lagoons. In response, grass carp were imported in 1963 to the United States Fish and Wildlife Service Fish Farming Experimental Station in Stuttgart, Arkansas, along with two other locations. At this facility, they experimented with the use of grass carp in controlling hydrilla and other submerged vegetation in fisheries’ aquaculture ponds. They proved to be an important tool in controlling vegetation in habitats with abnormally high nutrient loads (e.g. aquaculture ponds) or waterbodies with uncontrolled invasive non-native vegetation. However, they are more problematic in waterbodies with low nutrients or waterbodies without high quantities of invasive plants.

Flooding allowed grass carp to escape this facility into the Lower White River in 1966. Around this time, grass carp were being bred at the Lonoke Fish Hatchery, and shortly after followed the first stockings into Arkansas lakes. Soon after, the uncontrolled grass carp populations started wreaking havoc on natural habitats that lacked excess weeds, which, in turn, began to impact other game species. Between 1972 and 1980, scientists and government agencies further researched the production of sterile grass carp. In 1985, sterile triploid grass carp were created by temperature shocking an egg immediately after fertilization. This temperature shock causes the fertilized egg to retain the extra set of chromosomes (or DNA) that is usually extruded shortly after fertilization. This results in 72 instead of 48 chromosomes, making the carp unable to reproduce. After 1985, only triploid carp were used for aquatic vegetation management with many states requiring certification of each fish as triploid.

Today in Arkansas, grass carp are considered “invasive” to river systems but allowed in lake or reservoir systems with a need for aquatic vegetation control. In 2024, the Arkansas Game and Fish Commission funded the Arkansas Carp Incentive Program 2024 for commercial fisheries operations on the Arkansas River. This program aims to reduce the distribution and expansion of all Carp species in Arkansas (silver, bighead, black, and grass) by providing a subsidy for all invasive carp harvested and sold by commercial anglers or by providing start-up fishing supplies to target carp species.

History in Bella Vista:

Grass carp have been stocked in all Bella Vista Lakes, but more heavily in Loch Lomond. Stocking records indicate that grass carp were stocked on a rotation from 2009 to 2011 to control any renegade aquatic nuisance vegetation. Grass carp were not stocked again until 2017 when aquatic nuisance vegetation started to build on Loch Lomond. In the spring of 2019, the invasive plant parrot-feather began to proliferate in the Tiree arm of Loch Lomond. Parrot-feather is a highly invasive non-native plant that is usually sold in the aquarium trade and can quickly grow from fragments or cuttings from a mother plant. For this reason, grass carp was stocked heavily in Loch Lomond from 2019 to 2020 to combat the uncontrolled weed growth from dense, fragmenting parrot-feather. To eradicate an invasive plant species like parrot-feather, grass carp need to be stocked in larger numbers than is normally recommended. It is important for residents to dispose of non-native aquarium plants and animals in an appropriate and humane manner that does not involve releasing into local water bodies. They should also not raise these plants and animals in ponds that may connect to another waterbody. Aquatic plants in uncontrolled environments can become invasive, outcompeting other better suited and more balanced natural vegetation. Additionally, it can cause significant problems for lake users by clogging boat engines, inhibiting the natural beauty of water bodies, and/or interfering with other recreation activities.

By: Kayla Sayre, Bella Vista POA Fisheries & Water Quality Sr. Technician