Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch11 ◽

2011 ◽

Keyword(s):

North America ◽

Grass Carp ◽

Silver Carp ◽

Federal Agencies ◽

Bighead Carp ◽

Commercial Fish ◽

Fish And Wildlife Service ◽

In The Wild ◽

Asian Carps ◽

The U.S

Abstract.—Numerous natural resource agency and media reports have alleged that Asian carps were introduced into the wild through escapes from commercial fish farms. This chapter traces the chronology associated with importations of Asian carps to North America and discusses the likeliest pathways of their introduction to the wild. The U.S. Fish and Wildlife Service first imported an Asian carp species, grass carp Ctenopharyngodon idella, in 1963. Since then, state and federal agencies, universities, and private fish farmers have interacted to import Asian carps, to develop production technologies, and to promote their use in both public and private sectors in a number of different states. These importations and stocking, whether in confinement or, in the case of the grass carp, sometimes in open waters, were purposeful and legal. Asian carps were introduced to take advantage of their unique food preferences (planktivory by silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis, herbivory by grass carp, and molluscivory by black carp Mylopharyngodon piceus). The first known accidental release of diploid grass carp was in 1966 by the U.S. Fish and Wildlife Service in Stuttgart, Arkansas. Other early reports of grass carp in the wild were from waters in Alabama, Georgia, and Florida. Grass carp were reported from the wild in 1970, 2 years before the first private hatchery received grass carp. By 1972, grass carp had been stocked in open water systems in 16 different states. Silver carp and bighead carp were first imported purposely by a commercial fish producer in Arkansas in 1973. All silver and bighead carps were transferred to the Arkansas Game and Fish Commission by March 1974 where they first successfully spawned silver carp and bighead carp later that year. The first report of silver carp in the wild was in Arizona in 1972, although strong evidence suggests that this may have been a misidentification, followed by reports in Arkansas in the wild in 1975. The Arkansas report occurred 2 years before bighead carp and silver carp were returned to private hatcheries for commercial production. By 1977, silver carp and bighead carp had been introduced to Alabama, Arizona, Arkansas, Illinois, and Tennessee. Research and stockings of silver carp and bighead carp were conducted by at least six state and federal agencies and three universities in seven states in the 1970s and 1980s. Public-sector agencies, which were successful in encouraging development and use of Asian carps that today are in commercial trade, are the likeliest pathways for the earliest escapes of grass carp, silver carp, and bighead carp.

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Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch18 ◽

2011 ◽

Keyword(s):

North America ◽

Grass Carp ◽

Silver Carp ◽

Nuclear Size ◽

Bighead Carp ◽

Ctenopharyngodon Idella ◽

Wild Populations ◽

Black Carp ◽

Pass Through ◽

Asian Carps

Abstract.—The Asian black carp Mylopharyngodon piceus is of interest to the aquaculture industry in the United States as a biological control for snails and mollusks. However, past experience in North America with other Asian carps has raised concern that black carp will establish wild populations and negatively affect native populations of fish and invertebrates, especially mollusks. The demand for black carp has led biologists to seek ways to allow their use while at the same time maintaining control over their distribution and reproduction. Physical containment and restrictions on importation, release, and stocking have mostly failed. Control of reproduction holds more promise. The induction of triploidy (having three sets of chromosomes), which can render an individual biologically sterile, is of particular interest. The main purpose of this study was to evaluate the efficiency of proposed testing procedures used to assure genetic triploidy in black carp prior to distribution by the state of Missouri, using black carp and grass carp Ctenopharyngodon idella. Our objectives were to (1) verify if the ploidy determination methodology (nuclear size) employed was 100% accurate, (2) determine growth and survival of juvenile black carp over extended periods of time under laboratory and pond conditions, and (3) histologically examine development and gametogenesis in gonads collected from triploid and diploid black and grass carps of different ages and stages of maturation. Comparison of erythrocyte nuclear size using the Coulter counter method versus the more accurate method of flow cytometry that measures DNA content indicated an error rate of 0.25% by the former method. Black carp grew and survived well in mid-Missouri ponds. Triploid grass carp males appeared to produce functional gametes, and some triploid black carp male testes had apparently normal spermatocytes within cysts. A few normally developing oocytes at previtellogenic and vitellogenic stages were observed in triploid grass carp females, and a few normal perinuclear oocytes could be identified in triploid black carp females. Currently, the standards of the U.S. Fish and Wildlife Service’s triploid grass carp voluntary inspection program are being followed by some states to manage triploid black carp. Our results indicate that although the percentage of diploid black carp that could pass through the currently proposed screening program is small, overall numbers of diploid black carp distributed in a state could be substantial depending on the number of triploids distributed. Furthermore, despite indications that triploid male black carp can be expected to be functionally sterile, reproductive studies may be warranted given the large wild populations of diploid grass carp, bighead carp Hypophthalmichthys nobilis, and silver carp H. molitrix in the Mississippi River basin system.

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Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch3 ◽

2011 ◽

Keyword(s):

Great Lakes ◽

Mississippi River ◽

Silver Carp ◽

Bighead Carp ◽

Ctenopharyngodon Idella ◽

Great Lakes Basin ◽

Black Carp ◽

Federal Department ◽

In The Wild ◽

Asian Carps

Abstract.—There are four species collectively known as the Asian carps: grass carp Ctenopharyngodon idella, bighead carp Hypophthalmichthys nobilis, silver carp H. molitrix, and black carp Mylopharyngodon piceus. These species have been introduced worldwide for aquaculture purposes. Subsequent to introduction into the southern United States, three species have become well-established in the wild (grass, bighead, and silver carps). Two of these species, bighead and silver carps, have been dispersing rapidly up the Mississippi River basin, wreaking ecological havoc along the way. As there are numerous connections between the Mississippi basin and Canadian watersheds, including the Great Lakes, there is considerable concern about their potential ecological impacts if introduced and established in Canada. In addition to natural dispersal, these species may also be introduced into the Canadian wild through the live food fish trade. In 2004, the Canadian federal department of Fisheries and Oceans Canada conducted a risk assessment to determine the ecological risk of Asian carps to Canada. This assessment included evaluating the risk of survival, reproduction and spread of these species, as well as their pathogens, parasites, or fellow travelers (e.g. other invasive species), should they be introduced into Canada. These components were assessed in an expert workshop using best available information on their biology, potential vectors of introduction, and impacts in both native and introduced ranges. The assessment concluded that the risk of impact was high in, at least, some parts of Canada, including the southern Great Lakes basin by all four Asian carp species.

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Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch17 ◽

2011 ◽

Keyword(s):

Grass Carp ◽

Juvenile Fish ◽

Silver Carp ◽

Reproductive Potential ◽

Asian Carp ◽

Bighead Carp ◽

Ctenopharyngodon Idella ◽

Market Demand ◽

Black Carp ◽

Asian Carps

Abstract.—In the 1970s, commercial fishers reported sightings of grass carp Ctenopharyngodon idella in large rivers and associated backwaters of Louisiana; the first specimen in Louisiana Department of Wildlife and Fisheries’ fishery independent sampling was recorded in 1976. Beginning in the early 1980s, commercial fishers noted increasing populations of bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix (together, the bigheaded carps). Populations of bigheaded carps appear to be increasing at a much slower rate than in the Midwest¸ possibly due to limited suitability of and access to backwater habitat for juvenile fish. In 2002, harvester reports of sporadic captures of “different-looking” grass carp indicated the possible presence of black carp Mylopharyngodon piceus. Because both normal diploid and triploid (in which triploidy has been induced to cause sterility) black carp have been stocked in the Mississippi basin, determination of the ploidy (number of chromosome sets) of these fishes is important. Since 2002, postmortem ploidy determinations using cells from eyeballs removed from six wild black carp captured in Louisiana showed each to be a normal diploid, indicative of breeding capability and potential reproducing populations. Although reported commercial landings of grass and bigheaded carps have been as high as 34,830 kg/year, limited market demand in past years resulted in many captures being discarded. A protocol for obtaining samples for easily determining ploidy is reported here. Accurate data on Asian carp distributions and their reproductive potential provides information to fisheries researchers that will be constructive in documenting the spread of these invasive species and in the assessment of risk to habitats.

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Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch15 ◽

2011 ◽

Keyword(s):

North America ◽

Silver Carp ◽

Free Field ◽

Bighead Carp ◽

Skin Extract ◽

Field Observations ◽

Total Length ◽

Hypophthalmichthys Nobilis ◽

Avoidance Tests ◽

Asian Carps

Abstract.—The response of bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix to conspecific skin extracts was determined during free-field observations and avoidance tests. The extracts induced freezing/motionlessness, cessation of food-searching activities, and reduced swimming activity in the fish. Silver carp tended to avoid the area where the extract was released and a strong schooling response was induced in bighead carp. In avoidance tests using countercurrent chambers, young bighead carp (5–8 cm total length) were unresponsive to the skin extract (P > 0.05). However, in both species, older juveniles (12–25 cm total length) spent significantly less time (P < 0.01) in the side of the chamber receiving skin extract solutions. The extract was effective whether freshly prepared or aged at room temperature for 24 h. Freezing did not alter the effectiveness of fresh or frozen extracts. These studies suggest that bighead and silver carp are responsive to conspecific skin extracts and that the use of extracts might be useful to repel carp from habitats of concern.

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Invasive Asian Carps in North America

Invasive Asian Carps in North America ◽

10.47886/9781934874233.ch13 ◽

2011 ◽

Keyword(s):

United States ◽

North America ◽

Silver Carp ◽

The United States ◽

Bighead Carp ◽

Hypophthalmichthys Nobilis ◽

Asian Carps

Abstract.—In the United States, a variety of outreach has been done on bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix by a number of organizations and institutions. Because many of these outreach efforts were localized, nonlocalized entities often are unaware of them. Many of the entities conducting outreach, too, do not have a systematic bighead and silver carp (BSC) outreach plan and thus their efforts may not be as efficient or effective as possible. To address these issues, we surveyed organizations in areas where BSC have been found and compiled the reported BSC outreach activities. We then created a comprehensive outreach plan as a template for those conducting BSC outreach and compared it to existing efforts. In this comparison, we found that (1) targeted audiences could be more narrowly focused, (2) easily accessible tools could be more fully utilized, and (3) systematic evaluations need to be conducted to ensure that outreach efforts are being effective. We hope that this compilation and the comprehensive outreach plan will help improve the collective future BSC outreach, making it more efficient and effective.

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