Locations and Impacts of 4 Invasive Carp Species

Grass Carp



http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=514

Grass carp populations have been recorded in 45 states including the Great Lakes region of the United States (Lake Huron and Lake Ontario).  The only states that these carp haven't been introduced to are Alaska, Maine, Montana, Rhode Island, and Vermont.  

     -Negative effects involving grass carp included interspecific competition for food with invertebrates (e.g., crayfish) and other fishes, significant changes in the composition of macrophyte, phytoplankton, and invertebrate communities, interference with the reproduction of other fishes, decreases in refugia for other fishes, and so on.

     -Grass carp seem to affect other animal species by modifying preferred habitat, an indirect effect.

     -Grass carp may directly influence other animals through either predation or competition when plant food is scarce.  Grass carp have significantly altered the food web and trophic structure of aquatic systems by inducing changes in plant, invertebrate, and fish communities.

     -Large populations of grass carp decreases the density and composition of aquatic plant communities.

     -Organisms requiring limnetic habitats and food webs based on phytoplankton tend to benefit from the presence of grass carp.

     -Declines have occurred in the diversity and density of organisms that require structured littoral habitats and food chains based on plant detritus, macrophytes, and attached algae.

     -Removal of vegetation can have negative effects on native fish, such as elimination of food sources, shelter, and spawning locations.

     -Although grass carp are often used to control selected aquatic weeds, these fish sometimes feed on preferred rather than on target plant species.

     - Increases in phytoplankton populations is a secondary effect of grass carp presence.

     -A single grass carp can digest only about half of the plant material that it consumes each day. The remaining material is expelled into the water, enriching it and promoting algal blooms.  These blooms can reduce water clarity and decrease oxygen levels in the water.

     -Grass carp may carry several parasites and diseases known to be transmissible or potentially transmissible to native fishes.

      Black Carp

http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=573

The black carp has been reported in Arkansas, Illinois, Mississippi, and Missouri.  There appears to be no existing, economically feasible method to completely eliminate black carp populations once they escape into large river systems. 

     -There is high potential that the black carp would negatively impact native aquatic communities by feeding on, and reducing, populations of native mussels and snails, many of which are considered endangered or threatened.

     -Given their size and diet preferences, black carp have the potential to restructure benthic communities by direct predation and removal of algae-grazing snails.

     -Based on the fact that black carp attain a large size (well over 3 feet long), both juvenile and adult mussels and snails of many species would be vulnerable to predation by this fish.

     -The effectiveness of black carp in significantly reducing snail populations in aquaculture ponds indicates that any black carp occurring in the wild may cause significant declines in certain native mollusk populations in North American streams and lakes.

Bighead Carp

http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=551

This species has been recorded from within, or along the borders of, at least 18 states. There is evidence of reproducing populations in the middle and lower Mississippi and Missouri rivers and the species is apparently firmly established in the states of Illinois and Missouri.

     -These carp have the potential to deplete zooplankton populations.  A decline in the availability of plankton can lead to reductions in populations of native species that rely on plankton for food, including all larval fishes, some adult fishes, and native mussels.  



Silver Carp

http://nas.er.usgs.gov/queries/speciesmap.aspx?SpeciesID=549

Populations of silver carp have been recorded in 12 states.

     -In numbers, the silver carp has the potential to cause enormous damage to native species because it feeds on plankton required by larval fish and native mussels.

     -This species would also be a potential competitor with adults of some native fishes, for instance, gizzard shad, that also rely on plankton for food.

     -Silver carp also have the potential to impact certain regions such as the Great Lakes region economically. 

  

Types of Asian Carp

"Asian Carp" is a general term refering to a number of related carp species native to Asia and some regions of Europe.  Here I have included a list of some of these carp and a basic description of each.

Grass Carp



In the United States, this fish is also known as the White Amur.  It was introduced to the United States for aquatic weed control.  Grass carp grow very rapidly, reaching approximently 3.9 feet when fully mature and weighing up to 40 pounds.  These big eaters consume almost three times their body weight each day.  Grass carp thrive in backwaters and small lakes where aquatic vegetation is abundant as a food source.

Common Carp



The wild populations of common carp in the Eurasian continent are considered to be vulnerable for extinction; at the same time, however, they are also considered to be invasive species in the United States and other countries worldwide.  They can grow to lengths of approximently 47 inches long and can weigh up to 88 pounds as an adult.  Common carp are very tolerant of most conditions, but they prefer living in large bodies of slow-moving water.  Common carp are also omnivorous eating both water vegetation such as plankton and and small organisms such as insects and crayfish.

Silver Carp



Pound for pound, more silver carp are produced worldwide in aquaculture than any other species of carp.  Silver carp are filter feeders, feeding primarily on phytoplankton and zooplankton.  Because of their eating habits, silver carp have been used to successfully control water quality.  The silver carp is also called the "flying carp" for its tendency to leap from the water when startled.  They can grow to over 40 pounds and can leap up to ten feet from the water.

Bighead Carp



Bighead carp have  large scaleless heads, a large mouth, and eyes located very low on the head.  They tend to have a mottled gray colaration as adults.  Bighead carp can weigh over 100 pounds.  These carp are closely related to silver carp being that they are both filter-feeders eating primarily phytoplankton and zooplankton.   Bighead carp are not always considered undesirable invasive species when they are introduced outside their native range, and they continue to be stocked in some waterbodies to support commercial fisheries.  Stocking bighead carp in fisheries usually increases the total biomass of fish available for harvest.

Black Carp

Black carp typically grow up to 3 feeet in length and can weigh up to 70 pounds as an adult.  This fish generally feed on snails mussels.  In China, black carp are the most highly esteemed and expensive foodfish among the "four domestic fishes"and, partly because of its diet and limited food supply, is the most scarce and expensive in the marketplace.  Black carp are considered to be a serious threat to mollusks native to the United States, many of which are critically endangered. In 2007, the black carp was listed as an "injurious species" under the Lacey Act. It is thus illegal in most cases to transport live black carp, whether sterile or fertile, into the United States or across state lines.

Common Goldfish

 Common goldfish come in a variety of colours including red, orange/gold, white, black and yellow.  This species of carp is a common pet fish species all over the world.  Common goldfish are social animals who prefer living in small groups.  Goldfish can have lifespans up to 20+ years if they are fed a varied diet and housed in exceptional water conditions.  The oldest recorded goldfish was 43 years old.