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Figure 41. Black Carp, SIUC 46739, 390 millimeter SL, from Randolph County, Missouri.
The Black Carp (fig. 41) is a large cyprinid, often exceeding 1 m SL. The reported maximum size is about 2 m TL and 70 kg (Nico and others, 2005). The body is somewhat stout, rather elongate, and cylindrical to slightly compressed with a short and relatively deep caudal peduncle. The scales are relatively large, ranging from 39-46 along the lateral line. The head is relatively short, with eyes of moderate size. The snout is slightly rounded. The mouth is relatively small to moderate in size, placed terminally or slightly subterminally, and lacking barbels. Gill rakers are short and stout, usually numbering 18-21 (range 14-23). The short dorsal fin has iii (7-9) rays. The anal has iii (7-9) rays. The dorsalfin origin is slightly anterior to pelvic-fin origin. The caudal fin is large and forked. Body coloration is somewhat variable. Typically, individuals are dark brown or blue-gray to black and the fins, in particular, are darkly pigmented (fig. 42). Meristics for Black Carp are given in appendix B (also see Nico and others, 2005).
The pharyngeal teeth generally form a single row of four or five large molariform teeth per side (fig. 43). Occasionally an outer (secondary) row is present, consisting of a single tooth (possibly two in rare instances) on one or both sides. Dentition formula is typically 0,4-5,0 or 1,4-4,1. Juvenile and adult Black Carp (31-330 mm TL) pass through several generations of pharyngeal teeth (Liu and others, 1990). In small Black Carp (<30 mm TL), the pharyngeal teeth may be conical.
During the reproductive season, male Black Carp develop breeding or nuptial tubercles, although these may not always be observable (Bardach and others, 1972). Breeding tubercles have been reported on the interorbital region, pectoral-fin rays, operculum, and sides of the body (Kimura and Tao, 1937; Wu and others, 1964b; Chang, 1966; Zhong and others, 1980). Tubercles are absent in females (Chang, 1966).
Figure 42. Black Carp (261 millimeter SL) from the species’ native range
Figure 43. Pharyngeal teeth of Black Carp, SIUC
Few native North American fishes can be confused with Black Carp. Its large adult size distinguishes Black Carp from most native minnows, although a few large catostomids (suckers) and cyprinids have a body shape superficially resembling Black Carp. Several native fishes have heavy pharyngeal teeth modified for feeding on mollusks, similar to Black Carp. Nevertheless, in all cases the combination of size, number, shape, and placement of the pharyngeal teeth of native species is different from that found in Black Carp.
The Black Carp is most similar to its close relative, the Grass Carp, particularly in terms of body size and shape, and the position and size of fins and eyes (Nico and others, 2005). Anatomy of the pharyngeal teeth is the main characteristic used to distinguish the two species, although body color differences may also be useful. Pharyngeal teeth of Black Carp (about >30 mm TL) are large, molariform, and relatively smooth (without grooves or hooks of any kind; fig. 43), whereas those of Grass Carp are elongate with grooves or serrations. Small Black Carp (about <30 mm TL) have pharyngeal teeth that are somewhat conical and could be confused with the teeth of Grass Carp.
The body and fins of Grass Carp are generally lighter in color than those of Black Carp; however, color may vary with age, habitat, and season (Nico and others, 2005). Whereas the Black Carp is rather darkly colored, the Grass Carp is olivaceous, silvery white, or olivebrown above and silvery below, with most fins only partially pigmented (sometimes described as dusky). In both species, the body is counter-shaded, lighter below than above. In some Black Carp, the ventral part of the body may appear almost white, particularly beneath the head region. Although little information exists on color differences between juvenile Black Carp and Grass Carp, color pattern is probably less reliable in distinguishing between small juveniles of the two species, because of habitat influence. For example, Grass Carp inhabiting tannic waters (sometimes referred to as “black water”) typical of the southern U.S. can be darkly pigmented and confused with Black Carp.
Descriptions of Black Carp in the literature and our own examination of live and preserved specimens indicate that a few other traits may be useful in distinguishing Black Carp from Grass Carp. However, not all of these differences have been adequately confirmed (Nico and others, 2005). Moreover, these additional traits may exhibit more variation than pharyngeal teeth and, therefore, are appropriately used only in combination with teeth anatomy and body color. These additional traits include: number and relative size of gill rakers, shape of head and snout (for example, interorbital width and head length), relative length of the intestine, and color of the peritoneum. Howells (1992) reported that differences in gill-raker counts distinguish Black Carp from Grass Carp. However, our review of the literature and counts on specimens indicate there is overlap, with Black Carp having 14-23 (usually 18-21) gill rakers, and Grass Carp typically having 12-16. Gill rakers in both species are relatively small, but an examination of 30 Black Carp and 30 Grass Carp revealed that those of Black Carp were slightly shorter and stouter. Slight differences in the shape and slope of the head have been observed. For example, our measurements of preserved specimens (about 80-100 mm SL) indicate that the ratio of the interorbital width (IOW) divided into head length (HL), may be a useful distinguishing characteristic. Measurements ranged from 35-45 percent in Black Carp versus 48-56 percent in Grass Carp. Black Carp have a relatively short digestive tract (intestinal length is about 1-2 times TL), whereas Grass Carp have a longer, more coiled digestive tract (intestinal length about 2.5 times TL; Nico and others, 2005). Based on our own observations and information in the literature, the peritoneum of juvenile and adult Black Carp is dark, whereas in Grass Carp the membrane is generally silver, although heavily mottled with black (fig. 10 in Key).
There are no recognized subspecies for Black Carp. However, Biro (1999) suggested that differences in pharyngeal teeth counts provide possible evidence for two subspecies in China.
Hybrids in nature have not been reported. However, the Black Carp has been artificially crossed (with limited success) with Grass Carp, Silver Carp, Bighead Carp, Common Carp, and Black Bream (Megalobrama terminalis; Ryabov, 1979; Evtushenko and others, 1994; Biro, 1999; Nico and others, 2005).
The reproductive requirements of Black Carp are similar to those of Grass Carp (Nico and others, 2005). Please refer to section entitled “Spawning requirements of Chinese carps” in the Grass Carp account.
The Black Carp is a large cyprinid, often exceeding 1 m SL and with a maximum size of about 2 m TL and 70 kg (Nico and others, 2005). The typical habitat includes reaches of large rivers that are below 200 m above sea level (Li and Fang, 1990), such as channels of lowland rivers and associated floodplain lakes and backwaters. The species also occurs in artificial habitats (including canals), and some populations survive in lakes and reservoirs, although reproduction and completion of their life cycle require a connection to flowing waters (Nico and others, 2005).
Nico and others (2005) reviewed information on the environmental tolerances of Black Carp. The species is tolerant of temperatures from about 0.5-40 °C. Reproduction and egg development generally occur between 18-30 °C. The Black Carp is known to occasionally inhabit the deltas of rivers (for example, Yangtze River, China), where it may encounter brackish waters. However, information on salinity tolerance of Black Carp has not been reported.
The species is tolerant of pH from 6-10 for limited periods of time; however, the preferred range is from 7 or 7.5-8.5. Black Carp is tolerant of oxygen levels as low as 2 mg/L.
The diet of Black Carp was reviewed by Nico and others (2005). Larvae and small juveniles feed almost entirely on small invertebrates (such as zooplankton and aquatic insects). Larger juveniles and adults are bottomfeeders that predominantly prey on snails and bivalve mollusks, although crayfish and other benthic invertebrates are sometimes consumed. The heavy pharyngeal arches and large molariform teeth of Black Carp are adapted to crush mollusk shells (Liu and others, 1990; Nico and others, 2005).
The native range of Black Carp includes most major Pacific Ocean drainages of eastern Asia from the Amur River Basin south to the West-Pearl River Basin, and possibly the Red River of northern Vietnam (Nico and others, 2005).
Black Carp was first imported into the U.S. in the 1970s, and by the 1990s the species was being used in fish farms in several southern states to control pond snails (Nico and others, 2005). Thirty Black Carp were reported as having escaped into the Osage River from a Missouri fish farm during a major flood in April 1994. Because of its widespread use to control snails, escapes from aquaculture ponds have probably added to the wild population. During recent years there have been reports of Black Carp being captured in the wild. The first published report was that of a single Black Carp taken by a commercial fisher from Horseshoe Lake in southern Illinois in March 2003 (Chick and others, 2003). Nico and others (2005) investigated other reports and found evidence that wild populations of Black Carp may have been present in the lower Mississippi River Basin, largely in and around the Red River of Louisiana, since the early 1990s. Reproduction in the Mississippi River has not been documented, but new information and recent collections suggest the species is likely established in the lower part of the Mississippi Basin and possibly elsewhere in the basin (Nico and others, 2005).
Plate 9. Distribution of Black Carp in the United States. See Methods for details regarding data
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