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Asian Carp – Invasive Species – Part 7

Invasion of Alien Species in USA Waterways - Part 7

Asian Carp

Asian Carp swimming in clear water

The Asian Carp consists of various sub species including the Grass Carp (Ctenopharyngodon idella), Common Carp (Cyprinus carpio), Silver Carp (Hypophthalmichthys molitrix), Bighead Carp (Hypophthalmichthys nobilis) and Black Carp (Mylopharyngodon piceus). Follow me to find out more about the asian carp as invasive species. Can you eat asian carp?

Invasive species Fish Jumping

Invasive Species Definition

The definition of an invasive species is any species that is not native to our ecosystems and cause harm when introduced to the ecosystems. Furthermore, these may include amphibians, plants, insects, fish, fungus, bacteria and more. Impacts on the environment may cause economic loss or affect human health.

While, Invasive species tend to grow and reproduce quickly and spread aggressively with the potential to cause harm on the environment, economy or even human health. Therefore, given the label “invasive”.

Grass Carp an invasive species eating grass

Grass carp is a sub-tropical to temperate species. Firstly, the species is native to large rivers and lakes in eastern Asia, Russia and northern Vietnam and from coastal waters inland. Has a Silver to Olive oblong body with moderately large scales and no head scales. Three simple and seven branched rays on the dorsal fin.

Can reach up to 80 pounds. Capable of invading new habitats and produce rapidly. Prefer spawning in large rivers instead of lakes or slower moving water but can bread in both. Able to eat up to 300 percent of its body weight. Therefore, poses a threat to native fish species.

Further, they spread disease to other fish and destroy the ecosystem by expelling plant waste into the water, dissolving the oxygen. Since, Grass carp are explosive breeders and prodigious feeders. Thus, Grass carp may out-compete indigenous species and take over native habitats.

Effect on Ecosystem

What does asian carp eat

The Asian Carp is able to eat up to 300 percent of its body weight. Therefore, poses a threat to native fish species. Further, they spread disease to other fish and destroy the ecosystem by expelling plant waste into the water, dissolving the oxygen. Since, Grass carp are explosive breeders and prodigious feeders. Thus, Grass carp may out-compete indigenous species and take over native habitats.

What does Asian Carp Eat? The grass carp feeds on vegetation and therefore eats all pondweed an other vegetative matter, destroying the ecosystem.

In addition, the invasive species disrupts ecosystems in that they only digest about half of the plant material that is consumed daily. Waste is expelled in the water. Thereby, increasing the nutrients which subsequently leads to algal bloom. Subsequently, lowering the water clarity and dissolved oxygen content.

Present in 45 states, except Alaska, Maine, Montana, Rhode Island and Vermont. A freshwater fish that prefers spawning in large rivers with turbid waters. No great distance migration is common. Prefer to congregate in specific areas.

Introduction of the Grass Carp to the USA

Swimming in darker waters

Grass carp was first imported to the United States to control macrophytes in aquaculture facilities. Soon escaping into waterways. Further, reports made in Missouri, Mississippi, Alabama and Arkansas. Rapid spread has resulted of widely scattered research projects.

Stockings by government agencies, unauthorized releases, interstate transport, escapes from farm ponds and aquaculture facilities and natural dispersal from introduction sites and the widespread stocking of grass carp as a biological control against nuisance aquatic plants in ponds and lakes.

Management in the USA of the Grass Carp

Harmful to native resources. Currently, only triploid (sterile) Grass carp are legal for use in Texas. Requiring a permit to obtain. An angler who catches the Asian Carp must immediately remove the intestines, except in waters where a valid Triploid Grass Carp Permit is in effect.

Should a Triploid Grass Carp be caught, they must immediately be returned to the water unharmed. Macrophyte maintenance still used Triploid Carp. These sterile fish pose no threat of reproduction. Grass Carp are prone to infections by Asian Tapeworm.

However, diploid, carp are still rampant throughout the United States and culling their numbers may prove a difficult task. However, you can eat asian carp in certain areas.

Anglers netting the invasive species to manage

The Common Carp, a heavy bodied fish weighing up to 75 lbs, originate from Europe and Asia. Generally, most individual fish weigh 8-10 lbs and a length of 12 – 25 inches. Size and weight increase with age.

Can reach and age of 47 years or more. Green, Yellow, Golden-Brown, Blue-Green or Silver with White or Yellow ventrally. Dorsal fin has 17-21 rays and an anal fin with spiny projections.

Common Carp

Spawn from April to June. Females lay between 100 000 and 500 000 eggs in 1 – 4 feet deep water under vegetation.  Larvae eat zooplankton and small crustaceans near the hatching area.

An Aggressive invasive species. Consume resources to the point of depletion. Have an omnivorous diet. Asian Carp uproots aquatic plants while feeding and consumes fish eggs.

Ecological Impact

Congregation in numbers of invasive species

Further, reduces the quality of water by releasing phosphorous and increasing algae. Which in turn, reduces native fish and plants species quality of life and as well as their populations. There are many different views on this carp species.

Ranges from invasive species to great sport fish. Found in streams and lakes with significant vegetation. Spot predators of bass and sun fish. Found in all mainland states. Common carp were introduced as a valued food source.

Furthermore, they have been introduced throughout the United States, accidentally or intentionally, allowing for their establishments across the States.

Management of the Common Carp

One of the best methods of control is utilizing the common carp as a food source. Prevention of disposing of unused bait in water and not releasing captured fish, can further reduce numbers.

It is not permitted to release any captive carp, but if a common carp is caught while fishing it is permitted to release it back into the original lake. With the Asian Carp diet, humans can eat asian carp.

Can you eat asian carp - fish being taken out in bucket
Silver Carp eating small fish

The silver carp, an Asian Carp, is native to Eastern Asia, Southern Russia and Eastern half of China. While, this is a heavy bodied fish that can weight up to 60 pounds. Has low-set eyes and an upturned mouth.

Mature at three. Moreover, reproduce until ten years of age. Spawning from May to September. Migrate upstream in groups of 15 to 20. While, streams are great sites to lay eggs. Where current is enough to transport eggs downstream.

Food and Behaviour

While, aggressive fish are able to eat up to half their body weight of plankton and detritus. Thereby, out competing native fish populations for resources. So, what do asian carp eat? Diet includes native mussels, larvae fish and adult fish. Able to jump several feet out of the water when disturbed by boaters.

Silver carp jump into boats of fishermen and injure people by jumping into them. Generally, found in freshwater ponds, sewage ponds, and eutrophic ponds. While, the diet consists of phytoplankton, zooplankton, bacteria, and detritus.

skimming the surface of the water. What does asian carp eat

Introduction and Management in the USA

Invasive Species Distribution

Introduced to the United States as a stock fish in Arkansas. While, their distribution now includes Alabama, Arizona, Colorado, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nebraska, South Dakota, Tennessee and Puerto Rico. However, popularity for stocking increased with records of six states, federal, and private facilities.

While, they are ideal for control of phytoplankton and as a food source. Accidental escapes happened. Furthermore, by 1980's waterways discovered these fish. Furthermore, the Spread, Sell or Import of these fish to United States is prohibited. Only permitted to release into the lake where caught.

Otherwise, it can be used as food. As adult, Silver carp can be identified by their violent jumping behaviour, displayed if disturbed by boats etc. Juveniles are difficult to distinguish from other native species of bait. To help prevent the spread of the invasive species, do not take live bait from lakes where silver carp are found. If you believe to have caught a silver carp in a new area, please contact local fish and wildlife department.

Bighead Carp

The Bighead carp are native to East Asian rivers and floodplains. An invasive, large-bodied, fast-growing, highly fertile, voracious-feeding and jumping fish. Characterized by having a stout body, large head, small downward-facing eyes and large opercles.

Has a smooth keel between the anal and pelvic fins that does not extend anterior of the base of the pelvic fins. Can weigh up to 45kg and reach 120cm in length. The size of this invasive species gives it an advantage over native fish in competition for food sources.

Use filter feeders in their gill rakers as screens to capture their prey. Their ventrally positioned eyes offer the fish the ability to see as it swims along the water surface scooping up zooplankton and phytoplankton. Meanwhile, ecosystems are at great risk.

These large, aggressive fish are capable of out competing native fish for resources. Are opportunistic feeders that consume high quantities of zooplankton and phytoplankton. Capable of rapid reproduction. Laying thousands of eggs at a time.

Introduction and Management in the USA

Used in aquaculture to control the populations of zooplankton and phytoplankton. As well as, food fish. In 1970s the United States introduced these fish. Ongoing invasions most commonly occur from escaped individuals that are raised for aqua-cultural purposes.

While, Juvenile fish are mistakenly used as bait fish. While, they get dislodge from the hook and may in turn populate a new habitat. The Great Lakes and Mississippi River among others, offer the necessary habitat for rapid growth in the population numbers of these fish.

Currently, recorded in 23 states rivers and tributaries. As well as, Canadian waters. The State and National Government Organizations have made great efforts to prevent the spread of this species.

Further, an electric barrier system design is in place to keep unwanted fish from entering the Great Lakes. Generally, creating an electric field with pulsing DC Current making swimming uncomfortable.

Management of invasive species by removing from water
Black Carp

The Black Carp, an Asian Carp native range to the Pacific Ocean and East Asia. Firstly, they are From the Amur River Basin south to the West-Pearl River Basin. They have elongated and laterally compressed blackish brown bodies with blackish grey fins.

Generally, more than 3 feet long and weigh around 33 pounds. They live for over fifteen years. Black Carp invade habitats and ecosystems readily due to a variety of factors. They are aggressive and prodigious feeders.

Consuming more than half of their body mass per day. Further, the invasive species is an explosive breeder. Gaining sexual maturity after a few years. Capable of laying hundreds of thousands of eggs in one brood.  Fertility and quantity of eggs increase with age.

Ecological Impact

Black Carp will negatively impact our native aquatic communities by feeding on them. Endangered and threatened populations of native mussels and snails are reducing in populations. Benthic communities can be restructured by direct predation and removal of algae grazing snails and native mussels.

Carp can become very large, growing to well over one meter long. Therefore, many juvenile and adult mussels and snails would be vulnerable to predation. Juveniles feed on zooplankton and insect larvae.

While, adults feed on bottom feeding invertebrates such as snails and mussels, so many different resources may become exhausted.

What does asian carp eat? looking for food in environment

Introduction and Management in the USA

Alert message on display regarding invasive species

Imported in 1970s for control of pond snails in the United States. Further, by the 1990s this species of fish was being used in fish farms in several southern states. Meanwhile, the fish escaped into the wild, supposedly during a major flood in Missouri. Further, sightings have been made in the United States freshwaters. Specifically, in The Great Lakes, Mississippi River, Louisiana, Arkansas, Illinois, Mississippi and Missouri.

Highly used in the aqua-cultural industry. Therefore, removal in the near future seems unlikely. Scientists have advised that triploid fish get used for farming purposes. So that, if these fish escape there is no widespread problem. Furthermore, diet of the invasive species enables humans to eat asian carp.

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