Asian carp

Asian Carp is a group several species of carp that are considered invasive species in the United States. Carp are oily freshwater fish of the family Cyprinidae. There are many kinds of carp have been substantially introduced outside of their native ranges, but those known as Asian carps in the US include four kind known as Grass carp, Bighead carp, Silver carp, and Black carp.

Asian carp were first introduced into the United States in 1963, where as bighead, silver, and black carp arrived in the 1970s. Four kinds of species escaped into the Mississippi River Basin, and all but the black carp are known to have developed self-sustaining populations. Green carp and bighead carp were captured in the Great Lakes Basin, but there was no evidence of reproduction to date.

Asian carp can live in a great variety of habitats including highly degraded areas. They are extremely spread because many countries have helped to make carp the most widely distributed freshwater fish in the world, They are extensively farmed in as Europe, Asia, Middle East, and also a popular angling fish in North America, Canada and Australia.

Body Design


There are many types of Asian carps, but the main ones are grass carp, bighead carp, silver carp, and black carp. Asian carps are very large fish, reaching lengths greater than 1m. The largest reported black carp was 70 kg! Asian carps have a single dorsal fin; pelvic fins are set back on the body; and the pectoral fins are low on the side. There is not an adipose fin. Asian Carps do not have teeth on their jaws; instead, the teeth are in the back of their throats, in a structure called the pharyngeal arch. They use these pharyngeal teeth and a masticatory pad located on the roof of the pharynx to process food.

These are the physical characteristics and descriptions of the four main types of Asian carp. The Bighead carp has a large scaleless head with an upturned mouth, no barbels, forward eyes that sit below the mouth and project downward, a scaleless keel that extends only from the anal fin to pelvic fin, very tiny scales, and long comb-like gill rakers. It is also dark gray, to silver white on the sides with many dark irregularly shaped blotches scattered over its body. The Silver carp has a scaleless head with large upturned mouth, no barbels, forward eyes that sit below the mouth and project downward, very small scales, gill rakers appear spongy, and its body is olive green; silver but sometimes bronze with red sides. The Grass carp has a broad, blunt head with a slight downturned mouth, no barbels, eyes that sit even with the mouth, no keel, a pointed dorsal fin, and large scales that are silver to gray with a prominent dark edge. Its body has a dark olive shading with brownish-yellow sides and a white belly. The Black carp has a broad, blunt head with a slightly downturned mouth, no barbels, no keel,a pointed dorsal fin, and dark-edged scales. It also has a blackish-brown to dark olive body, blackish-gray fins, and a white belly.

Life Cycle
Asian carps reproduce with an egg layer. For example, adult female of Common carp can lay 300,000 eggs in a single spawn. It can spawn multiple times in a season. Asian carp are usually spawn roe in the spring. response to rising water temperature(cold to warm) and rainfall, but can't spawn eggs anymore over early fall. A single Asian carp can lay over a million eggs in a year yet their population remains the same, so the eggs and young perish in similarly vast numbers. Eggs and fry often fall victim to bacteria, fungi, and the vast array of tiny predators in the pond environment. Carp which survive to juvenile are preyed upon by other fish such as the northern pike and largemouth bass, and a number of birds and ospreys and mammals.

These are the habitat of the some types of Asian carp, The Common carp prefer large bodies of slow or standing water and soft, vegetative sediments. As schooling fish, they prefer to be in groups of five or more. They naturally live in temperate climates in fresh or slightly brackish water with a pH of 6.5–9.0 and salinity up to about 0.5%, and temperatures of 3 to 35°C. The ideal temperature is 23 to 30°C, with spawning beginning at 17–18°C; they easily survive winter in a frozen-over pond, as long as some free water remains below the ice, the Grass carp mainly reproduce in water of 25°C (77°F).

Most of Asian carps have long life span, but it may live longer in accordance by nature environment or artificially. On average (artificially), Grass carp live up to 4~12 years, Black carp live up to 15 years, Silver carp live up to 20 years, and Common carp can live up to 12 years.

Ecology


Carp are large members of the minnow family. The invasive species group known in the US as Asian carp (Grass, Bighead, Silver, Black carps), originates from Eastern Russia and China. The common carp is a Eurasian relative. Asian carps naturally occur in a variety of freshwater habitats, including large rivers and warmwater ponds, lakes, and backwaters that receive flooding or are otherwise connected to large rivers. They also have been introduced widely to ponds, lakes, reservoirs, and canals, where they grow well but probably cannot spawn and recruit without access to an appropriate river habitat. Although their habitat is normally freshwater, Asian carps can tolerate low levels of salinity, dissolved salt content in water.

Invasive Behavior
There are four main types of Asian carp found in the U.S. Each of them having slightly different niches and behaviors. Grass carp are herbivorous, and feed on various different plant material. They can consume up to 40% of their body weight daily. Their affect on the environment can be devastating to native fish through the loss of large areas of aquatic plants. Grass carp aren't the only ones having negative affects on native species in the U.S. Altogether the three other main species will eat between 5-20% of their body weight daily. Black carp are directly affecting our endangered native mollusk populations. This species of carp preys upon our aquatic snail and mussel populations which can alter the way algae is naturally being removed in these ecosystems. Silver carp, as well as bighead carp consume a diet consisting mostly of plankton and algae. They also compete with native planktivorous fish, such as paddlefish and gizzard shad for this common food source. Invasive Asian carp seem to be rapidly taking over through their expansion. They are destroying ecosystems and showing horrible affects on native aquatic species.

Control Efforts
While there are still many "big ideas" as far as how to stop the invasion of Asian carp there are already practical solutions currently in use. Building fences might not seem like a high tech solution, however it is very practical. Building jersey barriers and chain link fences across rivers are one the of the main issues with it. It will only prevent carp from moving farther up river. In addition, it will also hurt businesses in the shipping industry. Some uses of this are currently in play. Another practical solution is currently in use by the state of Illinois by simply harvesting them. Governor Pat Quinn initiated a program to physically remove 30 million pounds of carp from his state. An electric shock barrier is in use 25 miles downstream of Chicago. It sends out 2 volts per square inch every 4 milliseconds.

Many invasion prevention technologies are currently in their developmental stages, one of which is a sound barrier. Due to their weberian apparatus (a small system of bones connecting the swimming bladder to the inner ear), Asian carp are very sensitive to sounds between 750 to 1500 Hz. This Sound Bubble Strobe or SBS will use LED lights and high pitch frequencies to spook carp downstream.There have also been attempts to poison these invasive species but there are currently no poison found to kill them.