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Oklahoma Invasive Species
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Silver Carp
Hypophthalmichthys molitrix

silver carp
Country of Origin: The silver carp’s native range includes eastern Asia from the Amur River in Russia to the Pearl River in China.
History: First introduced into the United States in 1973 by a fish farmer in Arkansas pond to control the level of phytoplankton as well as to provide a food fish.  By the end of the 1970’s some state, federal and private aquaculture facilities and even sewage lagoons had been stocked with silver carp.  It is believed that the silver carp found in natural waters are escapees from aquaculture facilities or to have entered as contaminant fish in grass carp stocks.  Populations in Hawaii and Colorado were also intentionally released.
Intended Use: To control the level of phytoplankton in some aquatic communities.
Mode of Invasion:

Its current distribution in the U.S. includes Alabama, Arizona, Arkansas, Colorado, Hawaii, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Nebraska, South Dakota, and Tennessee.  It has spread to most of the Mississippi River drainage including the Missouri and Ohio Rivers and their tributaries.  Anglers cast net for bait below the Texoma Dam and use the bait they catch to fish for stripped bass or catfish in Lake Texoma and Asian (Silver) carp can be accidentally introduced into the lake.  Silver carp have reproductive requirements similar to those of stripped bass so the potential for the establishment of a reproducing population in Lake Texoma is good and it could be devastating to the stripped bass community.

Species Description:

Silver carp are filter feeders that eat phytoplankton, zooplankton, bacteria, detritus and aquatic vegetation.  They live in freshwaters that are standing or slow moving.  They are sexually mature after 3 years and will breed until their maximum age of 10 years.  Spawning can occur anytime between April and September when the temperature is between 18-20 degrees Celsius.  They migrate upstream in groups of 15 to 20 fish and they need water with some current so the eggs and larvae can float downstream. 

Map of Occurrence:

map

Effects of Invasion: When the silver carp’s population numbers become large enough they can cause damage to the native species such as larval fish, mussels and some adult fish that rely on phytoplankton for food.  Natives such as paddlefish, gizzard shad and bigmouth buffalo will be affected.  Silver carp will jump from the water when disturbed which causes a hazard to water recreational users.  Also, this new species could bring diseases with it that native fish cannot survive.  Although adult silver carp mainly consume phytoplankton there have been reports of ponds stocked with silver carp increasing in phytoplankton biomass.  Typically this species is unable to ingest phytoplankton smaller than 10 µm.  If a stable breeding population was to form in a new location and the number of individuals grew, shifts in the food web structure could occur.  Silver carp were found to be an effective carrier of Salmonella typhimurium.
Control:

Navigation dams on the Mississippi have slowed their advance up the river.   The U.S. Army Corps of Engineers and the state of Illinois has built an electric barrier to stop the spread of the carp prompted by a fear of the carp disrupting the $4 billion fishing industry in the Great Lakes.  Agencies still need to educate the public about how to identify invasive species to stop the accidental release of silver carp.  Silver carp are not presently cultured in the U.S. largely because of their jumping habits and poor handling qualities during production, harvest, and transport.

References:

Aquatic Invasive Species : Silver Carp.  http://www.in.gov/dnr/fishwild/fish/ais/SILVER%20CARP.pdf

 

USGS Facts sheet about Bighead and Silver Carp. http://www.cerc.usgs.gov/pubs/center/pdfDocs/Asian_carp-2-2004.pdf

 

Oklahoma Dept. of Wildlife website - http://www.wildlifedepartment.com/asiancarp.htm

Gulf States Marine Fisheries Commission website, Hypopthalmichthys molitrix fact sheet - http://nis.gsmfc.org/nis_factsheet.php?toc_id=189

 

Asian Carp Management: Invasive Species Coordination website - http://www.asiancarp.org/

 

Carpbusters.com: Conservationists protecting native fish - http://www.carpbusters.com/profile_silver.shtm