details

Description

Bighead carp are invasive, large-bodied, fast-growing, highly fecund, voracious-feeding fish that are rapidly colonizing North American waterways. Notorious for their ability to jump out of the water, Asian carp are becoming more and more prevalent along the Mississippi, and substantial efforts are being made to prevent their introduction to the Great Lakes. Species within the genus Hypophthalmichthys, including: Bighead carp, H. nobilis, Silver carp, H. molitrix and Largescale Silver carp, H. harmandi are all characterized by having a stout body, large head, small downward-facing eyes (often below the jaw angle), and large opercles. The Bighead carp can be identified by a smooth keel between the anal and pelvic fins that does not extend anterior of the base of the pelvic fins. Bigheads can reach weights up to 45kg (~100lbs) and 120cm (~4ft) in length.

Ecological Threat

Bighead carp pose a great risk to novel ecosystems for several reasons. First, Bighead carp are large, aggressive fish that are capable of out-competing native fish for resources. Second, Bighead Card are opportunistic feeders that consume high quantities of zoo plankton and phytoplankton. And third, this species iscapable of rapid reproduction, laying up to thousands of eggs and one time.

Biology

Bighead carp filter feeder uses their specialized gill rakers as screens to capture their prey. Their ventrally-positioned eyes also offer the fish the ability to see as it swims along the water surface scooping up zooplankton or even phytoplankton.

Currently, Bighead carp have been recorded in 23 states, (including Texas), and some Canadian waters as well. In Texas, the fish have been reported in Bexar, Jones, and Taylor counties in the Upper San Antonio and Brazos river drainages. Besides large rivers, the carp are also found in smaller tributaries, especially near spillways.

Ongoing Bighead carp invasions most commonly occur from escaped individuals that are raised for aquacultural purposes. However, the fish may also enter open waters by way of bait fish. Juvenile Bigheads may be confused for Gizzard Shads or other native fish, and thus may mistakenly be used as bait. Individuals that dislodge from the hook may in turn populate a new habitat.

History

Brought to the United States in the early 1970s, Bighead carp were originally used in aquaculture to control the populations of zooplankton and phytoplankton, or even for use as a food fish. The first record of a Bighead carp caught in natural waters was in 1981 when an individual was caught on the Ohio River below Smithland Dam, Kentucky. That individual was believed to have escaped from a fish farm. Flooding, other natural disasters, and potential negligence has led to the escape of many more Bighead carp over the years.

Native Origin

Eurasia (specifically China)

Current Location

U.S. Habitat: Bighead carp are native to the large rivers and associated floodplains of East Asia. The Great Lakes and Mississippi River (and others), offer the necessary habitat for rapid growth in the population numbers of these fish.

Distribution

U.S. Present: Widespread across the United States, the Bighead carp has been reported in 23 states, including Texas. Breeding populations have been found along the Mississippi Waterway. It is unknown if breeding populations have become established in the Great Lakes, however Bighead carp have been sighted and/or captured in the area.

Texas: Bighead Carp have been spotted in the San Jacinto River, as well as in the Victor Braunig, Fort Phantom Hill, and Kirby Lake Reservoirs.

Resembles

Resembles many of the carp species in the United States. Including its Asian cousins:
the Grass carp (Ctenopharyngodon idella)
Silver carp (Hypophthalmichthys molitrix)
Largescale Silver carp (Hypophthalmichthys harmandi)
Black carp (Mylopharyngodon piceus)
Common Goldfish (Carassius auratus)
Crucian carp (Carassius carassius)
Mud carp (Cirrhinus molitorella)
Also resembles the Common carp (Cyprinus carpio) (Common carp are European and are sometimes considered "native" because they have been in the United States since the 1800s)

Management

Managing Bighead carp proves to be a rather difficult task. State and National Government organizations are making a strong effort to prevent the Bighead carp, as well as other invasive carp relatives, from entering the Great Lakes via the Chicago Waterway System which connects the Mississippi River to the Illinois River, and ultimately leads into the Great Lakes. In order to combat this, the US Army Corps of Engineers have constructed an electric barrier system designed to keep unwanted fish from entering the Great Lakes. The barriers use a pulsing DC current to create an electric field which is uncomfortable for fish to swim through. The hope is that the 3 barrier system can repel the Bighead carp from entering the Great Lakes. Currently, two of the three barriers are completed and operational, so time will tell about the system's efficacy.

References

SEARCH Online

Google Search: Hypophthalmichthys nobilis
Google Images: Hypophthalmichthys nobilis
NatureServe Explorer: Hypophthalmichthys nobilis
Bugwood Network Images: Hypophthalmichthys nobilis

References

Cindy S. Kolar, Chapman, Duane C., Courtenay Jr., Walter J., Housel, Christine M., Williams, James D., and Jennings, Dawn P. 2007. Bigheaded carp: Biological synopsis and environmental risk assessment. American Fisheries Society, Bethesda, MD.

Schrank, Sally, and Christopher Guy. 2002. Age, Growth, and Gonadal Characteristics of Adult Bighead Carp, Hypophthalmichthys nobilis, in the Lower Missouri River. Environmental Biology of Fishes. 64(4): 443-450.

Opuszynski, K., and J. V. Shireman.1993. Food habits, feeding behaviour and impact of triploid bighead carp, Hypophthalmichthys nobilis, in experimental ponds. Journal of Fish Biology. 42(4): 517-530.

Internet References