Bighead Carp

Diet and feeding

The FishTraits compilation records these diet categories for this species: algae or phytoplankton; detritus or unidentified plant material; invertebrates or larval fish. These are broad categories, not a claim that every individual consumes every example in a category.

Reported feeding positions include bottom feeding and surface or water-column feeding. The compilation combines published observations; diets can vary with age, locality, and available food.

Habitat preferences

Reported habitat associations include medium to large rivers.

The source records associations with open water. An association indicates reported use, rather than an exclusive requirement.

Reproduction and parental care

The compilation reports a representative maturity age of 4 years. Its maturity field summarizes mean, median, or modal estimates, usually for females; male estimates can be used when female data are unavailable. It is not a fixed age at which every fish first breeds.

Batch or serial spawning has been reported somewhere in the species’ range. This does not establish the same spawning pattern for every population.

Recorded spawning months are Apr, May, Jun for the source’s reporting region (MS). This is a regional calendar, not a range-wide schedule.

The reproductive-guild classification includes spawning on open substrates without guarding the brood.

Size and recorded longevity

FishTraits reports a maximum total length of 100 centimetres. Some entries use an estimated asymptotic length; this value should not be treated as a certified record catch.

Recorded longevity in the compilation is 10 years. Wild observations were preferred, but captive records were accepted where wild records were unavailable, and unspecified records were assumed wild. The value is not a guaranteed wild lifespan or an aquarium life expectancy.

Identification and appearance

It is very similar to Silver Carp (Hypophthalmichthys molitrix) and can be distinguished by the dark coloration on its side (vs. uniform silvery color) and a smooth keel between the anal and pelvic fins that does not extend forward past the base of the pelvic fins (vs. keel extends forward past the pelvic fin base). Adult Bighead Carp are unlikely to be confused with any North American native minnow species due to the large size and unusual position of the eye; however, juvenile Bighead Carp may be confused for a number of species including Common Carp (Cyprinus carpio), Goldfish (Carassius auratus), Gizzard Shad (Dorosoma cepedianum), and Golden Shiner (Notemigonus crysoleucas)

Native range

Southern and central China (Li and Fang 1990; Robins et al. 1991).

Habitat and ecology

The morphology of the Bighead Carp’s comb-like gill rakers and epibranchial organ allow this species to have a broad and flexible diet. This species is more efficient at filtering larger prey items like zooplankton and large phytoplankton, however in times of zooplankton scarcity Bighead Carp are capable of ingesting particles up to four times smaller than gill raker width (Opusyznski and Shireman 1991). Bighead Carp are also capable of consuming detritus, which in some cases has made up the dominant portion of their diet (Anderson et al. 2016; Boros et al. 2014; Calkins et al. 2012; Kolar et al. 2007).

Female Bighead Carp reach sexual maturity at three years of age, while males can reach sexual maturity in two years; however, this varies significantly with changing environmental conditions (Huet 1970; Kolar et al. 2007). Bigheaded carps are only known to spawn in large, turbulent rivers and it is believed that a rising hydrograph (flood event) is a primary spawning cue (Kolar et al. 2007). However, several studies have shown that rising water levels are not always necessary for spawning—indicating that these fish exhibit a phenotypic plasticity that may facilitate their successful establishment in novel ecosystems (Coulter et al. 2013; Kocovosky et al. 2012; Deters et al. 2012). Fecundity increases with age and body weight and is directly related to growth rate (Verigin et al. 1990). In its native range, Bighead Carp fecundity ranges from 280,000-1.1 million eggs. In North America, fecundity ranged from 4,792-1.6 million eggs (Kipp et al. 2011). Bighead Carp produce eggs that are semi-buoyant and require current to keep them from sinking to the bottom (Soin and Sukhanova 1972; Pflieger 1997). The eggs float for 40-60 hours before hatching.

Bighead Carp can grow rapidly in productive environments. In the Mississippi River, Bighead Carp grew to 1 kg in weight by age 2 and up to 852 mm in length by age 3 (Nuevo et al. 2004).

The oldest Bighead Carp recorded in the United States was believed to be 8-10 years old, and maximum age in China was reported to be 16 years. However, there is a lack of specific information regarding the longevity of this species and it is possible that they can be quite long lived (Kolar et al. 2007).

Introduction history

Bighead Carp were first imported into the United States in 1973 by a private fish farmer in Arkansas who wanted to use them in combination with other phytophagous fishes to improve water quality and increase fish production in culture ponds. In 1974 the Arkansas Game and Fish Commission and Auburn University, Alabama, obtained stock to assess their potential benefits and impacts (Jennings 1988). The species first began to appear in open waters, the Ohio and Mississippi rivers, in the early 1980s, likely as a result of escapes from aquaculture facilities (Jennings 1988). In April 1994, several thousand Bighead Carp, along with a few Black Carp Mylopharyngodon piceus, escaped into the Osage River, Missouri, when high water flooded hatchery ponds at an aquaculture facility near Lake of the Ozarks (Anonymous 1994). Fish that escaped into the Missouri River have increased and spread, since 1990, into the lower Kansas River of Kansas, and elsewhere (Cross and Collins 1995). The species may have dispersed into Oklahoma waters from fish illegally brought into southeast Kansas by a commercial fish farmer in 1988 (Pigg et al. 1993). According to Pigg et al. (1997), collections in the Grand River of Oklahoma since 1991 indicate a gradual downstream dispersal. The species was illegally stocked along with Grass Carp in one or a few ponds in California; these were brought into the state by a commercial aquaculturist. The live fish were reportedly transported in a concealed compartment under a load of black bass in the fall of 1989 from a fish grower in Oklahoma or Arkansas (Dill and Cordone 1997). The species was illegally stocked in Cherry Creek Reservoir, Colorado (P. Walker, personal communication).

Ecological impacts

Invasive carps have been shown to affect zooplankton communities (Burke et al. 1986, Lu et al. 2002, Cooke et al 2009; Calkins et al. 2012; Freedman et al. 2012; Sass et al. 2014).

Freedman et al. (2012) showed that resource use and trophic levels of the fish community change when invasive carps are present. They also demonstrated an impact on Bigmouth Buffalo and found isotopic values similar to Bluegill, Gizzard Shad, and Emerald Shiner.

Irons et al. (2007) showed significant declines in body condition of Gizzard Shad and Bigmouth Buffalo following invasion by Silver and Bighead carps. They state that ultimately, declines in body condition may decrease fecundity.