Genetically modified fish (GM fish) are
organisms
An organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been pr ...
from the taxonomic clade which includes the classes
Agnatha
Agnatha (; ) or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both extant taxon, living (Cyclostomi, cyclostomes such as hagfish ...
(jawless fish),
Chondrichthyes
Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...
(cartilaginous fish) and
Osteichthyes
Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...
(bony fish) whose genetic material (
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
) has been altered using
genetic engineering
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of Genetic engineering techniques, technologies used to change the genet ...
techniques. In most cases, the aim is to introduce a new
trait to the fish which does not occur naturally in the species, i.e.
transgenesis
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene delive ...
.
GM fish are used in scientific research and kept as pets. They are being developed as environmental pollutant sentinels and for use in aquaculture food production. In 2015, the
AquAdvantage salmon
AquAdvantage salmon is a genetically engineered (GE) fish, a GE Atlantic salmon developed by AquaBounty Technologies in 1989. The typical growth hormone-regulating gene in the Atlantic salmon was replaced with the growth hormone-regulating gen ...
was approved by the US
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
(FDA) for commercial production, sale and consumption,
[Staff (November 201]
FDA Has Determined That the AquAdvantage Salmon is as Safe to Eat as Non-GE Salmon
FDA Consumer Health Information / U.S. Food and Drug Administration / November 2015 / Retrieved 20 November 2015 making it the first
genetically modified animal
Genetically modified animals are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increasing resistance to disease, etc. The vast majority of genetically modified animals are at t ...
to be approved for human consumption. Some GM fish that have been created have promoters driving an over-production of "all fish"
growth hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...
. This results in dramatic growth enhancement in several species, including
salmonid
Salmonidae (, ) is a family of ray-finned fish, the only extant member of the suborder Salmonoidei, consisting of 11 extant genera and over 200 species collectively known as "salmonids" or "salmonoids". The family includes salmon (both Atlantic a ...
s,
carp
The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and a ...
s
and
tilapia
Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically mos ...
s.
Critics have objected to GM fish on several grounds, including ecological concerns, animal welfare concerns and with respect to whether using them as
food
Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...
is safe and whether GM fish are needed to help address the world's food needs.
History and process
The first transgenic fish were produced in China in 1985.
As of 2013, approximately 50 species of fish have been subject to genetic modification. This has resulted in more than 400 fish/trait combinations. Most of the modifications have been conducted on food species, such as
Atlantic salmon
The Atlantic salmon (''Salmo salar'') is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Hucho taimen, Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlan ...
(''Salmo salar''),
tilapia
Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically mos ...
(genus) and
common carp
The common carp (''Cyprinus carpio''), also known as European carp, Eurasian carp, or simply carp, is a widespread freshwater fish of eutrophic waters in lakes and large rivers in Europe and Asia.Fishbase''Cyprinus carpio'' Linnaeus, 1758/ref>Ark ...
(''Cyprinus carpio'').
Generally, genetic modification entails manipulation of
DNA
Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
. The process is known as
cisgenesis
Cisgenesis is a product designation for a category of genetically engineered plants. A variety of classification schemes have been proposed that order genetically modified organisms based on the nature of introduced genotypical changes, rather th ...
when a
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
is transferred between organisms that could be conventionally bred, or
transgenesis
Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene delivery must reach the genome of the host cell to induce gene expression. Successful gene delivery requires the foreign gene delive ...
when a gene from one species is added to a different species. Gene transfer into the genome of the desired organism, as for fish in this case, requires a vector like a
lentivirus
''Lentivirus'' is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in humans and other mammalian species. The genus includes the human immunodeficiency virus (HIV), which causes AIDS. Lent ...
or mechanical/physical insertion of the altered genes into the
nucleus
Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucleu ...
of the host by means of a micro syringe or a
gene gun
In genetic engineering, a gene gun or biolistic particle delivery system is a device used to deliver exogenous DNA (transgenes), RNA, or protein to cells. By coating particles of a heavy metal with a gene of interest and firing these micro-projec ...
.
Uses
Research

Transgenic fish are used in research covering five broad areas
*Enhancing the traits of commercially available fish
*Their use as bioreactors for the development of bio-medically important proteins
*Their use as indicators of aquatic pollutants
*Developing new non-mammalian animal models
*Functional genomics studies
Most GM fish are used in basic research in genetics and development. Two species of fish,
zebrafish
The zebrafish (''Danio rerio'') is a species of freshwater ray-finned fish belonging to the family Danionidae of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (an ...
(''Danio rerio'') and
medaka
The Japanese rice fish (''Oryzias latipes''), also known as the medaka, is a member of genus ''Oryzias'' ( ricefish), the only genus in the subfamily Oryziinae. This small (up to about ) native of Japan is a denizen of rice paddies, marshes, po ...
(Japanese rice fish, ''Oryzias latipes''), are most commonly modified because they have optically clear
chorion
The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It is also present around the embryo of other animals, like insects and molluscs.
Structure
In humans and other therian mammals, the cho ...
s (shells), develop rapidly, the 1-cell embryo is easy to see and micro-inject with transgenic DNA, and zebrafish have the capability of regenerating their organ tissues. They are also used in
drug discovery
In the fields of medicine, biotechnology, and pharmacology, drug discovery is the process by which new candidate medications are discovered.
Historically, drugs were discovered by identifying the active ingredient from traditional remedies or ...
. GM zebrafish are being explored for benefits of unlocking human organ tissue diseases and failure mysteries. For instance, zebrafish are used to understand heart tissue repair and regeneration in efforts to study and discover cures for
cardiovascular disease
Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumati ...
s.
Transgenic
rainbow trout
The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributary, tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout) is an Fish migration#Classification, ...
(''Oncorhynchus mykiss'') have been developed to study muscle development. The introduced transgene causes green fluorescence to appear in
fast twitch muscle fibres early in development which persist throughout life. It has been suggested the fish might be used as indicators of aquatic pollutants or other factors which influence development.
In intensive fish farming, the fish are kept at high stocking densities. This means they suffer from frequent transmission of contagious diseases, a problem which is being addressed by GM research.
Grass carp
The grass carp (''Ctenopharyngodon idella'') is a species of large herbivorous freshwater fish in the family Cyprinidae, native to the Pacific Far East, with a native range stretching from northern Vietnam to the Amur River on the Sino-Russian ...
(''Ctenopharyngodon idella'') have been modified with a transgene coding for human
lactoferrin
Lactoferrin (LF), also known as lactotransferrin (LTF), is a multifunctional protein of the transferrin family. Lactoferrin is a globular proteins, globular glycoprotein with a molecular mass of about 80 Atomic mass unit, kDa that is widely repre ...
, which doubles their survival rate relative to control fish after exposure to ''
Aeromonas
''Aeromonas'' is a genus of Gram-negative, Facultative anaerobic organism, facultative anaerobic, rod-shaped, bacteria that morphologically resemble members of the family Enterobacteriaceae. Most of the 14 described species have been associated w ...
'' bacteria and
Grass carp hemorrhage virus.
Cecropin
Cecropins are antimicrobial peptides. They were first isolated from the hemolymph of '' Hyalophora cecropia'', whence the term cecropin was derived. Cecropins lyse bacterial cell membranes; they also inhibit proline uptake and cause leaky membr ...
has been used in channel catfish to enhance their protection against several pathogenic bacteria by 2–4 times.
Recreation
Pets
GloFish
The GloFish is a patented and trademarked brand of fluorescently colored genetically modified fish, genetically modified aquarium fish. They have been created from several different species of fish: zebrafish were the first GloFish available in ...
is a patented technology which allows GM fish (tetra, barb, zebrafish) to express
jellyfish
Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...
and sea
coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...
proteins
giving the fish bright red, green or orange fluorescent colors when viewed in
ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...
light. Although the fish were originally created and patented for scientific research at the National University of Singapore, a Texas company, Yorktown Technologies, obtained the rights to market the fish as pets.
They became the first genetically modified animal to become publicly available as a pet when introduced for commercial in 2003. They were quickly banned for sale in California; however, they are now on shelves once again in this state. As of 2013, Glofish are only sold in the US.
Other transgenic lines of pet fish include
Medaka
The Japanese rice fish (''Oryzias latipes''), also known as the medaka, is a member of genus ''Oryzias'' ( ricefish), the only genus in the subfamily Oryziinae. This small (up to about ) native of Japan is a denizen of rice paddies, marshes, po ...
which remain transparent throughout their lives and pink body color transgenic angelfish (''
Pterophyllum scalare
''Pterophyllum scalare'', most commonly referred to as angelfish or freshwater angelfish, is the most common species of ''Pterophyllum'' kept in captivity. It is native to the Amazon Basin in Peru, Colombia, and Brazil. Particularly to the Ucayal ...
'') and lionhead fish expressing the Acropora coral (''
Acroporo millepora'') red fluorescent protein.
The ocean pout type III antifreeze protein transgene has been successfully micro-injected and expressed in goldfish. The transgenic goldfish showed higher cold tolerance compared with controls.
Food
One area of intensive research with GM fish has aimed to increase food production by modifying the expression of
growth hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...
(GH). The relative increases in growth differ between species.
(Figure 1) They range from a doubling in weight, to some fish that are almost 100 times heavier than the wild-type at a comparable age.
This research area has resulted in dramatic growth enhancement in several species, including
salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...
,
trout
Trout (: trout) is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of which are members of the subfamily Salmoninae in the ...
and
tilapia
Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically mos ...
.
Other sources indicate an 11-fold and 30-fold increase in growth of salmon and
mud loach, respectively, compared to wild-type fish.
Transgenic fish development has reached the stage where several species are ready to be marketed in different countries, for example, GM tilapia in Cuba, GM carp in the People's Republic of China, and GM salmon in the US and Canada.
In 2014, it was reported that applications for the approval of transgenic fish as food had been made in Canada, China, Cuba and the United States.
Over-production of GH from the
pituitary
The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus control much of th ...
gland increases growth rate mainly by an increase in food consumption by the fish, but also by a 10 to 15% increase in feed conversion efficiency.
Another approach to increasing meat production in GM fish is "
double muscling". This results in a phenotype similar to that of
Belgian Blue cattle in rainbow trout. It is achieved by using transgenes expressing
follistatin
Follistatin, also known as activin-bindings protein, is a protein that in humans is encoded by the ''FST'' gene. Follistatin is an autocrine glycoprotein that is expressed in nearly all tissues of higher animals.
Its primary function is the b ...
, which inhibits
myostatin, and the development of two muscle layers.
AquAdvantage salmon
In November 2015, the FDA of the USA approved the
AquAdvantage salmon created by
AquaBounty for commercial production, sale and consumption.
It is the first genetically modified animal to be approved for human consumption. The fish is essentially an Atlantic salmon with a single gene complex inserted: a growth hormone regulating gene from a
Chinook salmon
The Chinook salmon (''Oncorhynchus tshawytscha'') is the largest and most valuable species of Oncorhynchus, Pacific salmon. Its common name is derived from the Chinookan peoples. Other vernacular names for the species include king salmon, quinn ...
with a promoter sequence from an
ocean pout
The ocean pout (''Zoarces americanus'') is an eelpout in the family Zoarcidae. It is found in the Northwest Atlantic Ocean, off the coast of New England and eastern Canada. The fish has antifreeze proteins in its blood, giving it the ability to ...
. This permits the GM salmon to produce GH year round rather than pausing for part of the year as do wild-type Atlantic salmon.
The wild-type salmon takes 24 to 30 months to reach market size (4–6 kg) whereas the GM salmon require 18 months for the GM fish to achieve this.
[Environmental Assessment for AquAdvantage Salmon](_blank)
/ref> AquaBounty argue that their GM salmon can be grown nearer to end-markets with greater efficiency (they require 25% less feed to achieve market weight) than the Atlantic salmon which are currently reared in remote coastal fish farms, thereby making it better for the environment, with recycled waste and lower transport costs.
To prevent the genetically modified fish inadvertently breeding with wild salmon, all the fish raised for food are females, triploid
Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...
, and 99% are reproductively sterile. The fish are raised in a facility in Panama with physical barriers and geographical containment such as river and ocean temperatures too high to support salmon survival to prevent escape. The FDA has determined AquAdvantage would not have a significant effect on the environment in the United States. A fish farm is also being readied in Indiana where the FDA has approved importation of salmon eggs. As of August 2017, GMO salmon is being sold in Canada. Sales in the US began in May 2021.
Detecting aquatic pollution (potential)
Several research groups have been developing GM zebrafish to detect aquatic pollution. The laboratory that developed the GloFish originally intended them to change color in the presence of pollutants, as environmental sentinels. Teams at the University of Cincinnati
The University of Cincinnati (UC or Cincinnati, informally Cincy) is a public university, public research university in Cincinnati, Ohio, United States. It was founded in 1819 and had an enrollment of over 53,000 students in 2024, making it the ...
and Tulane University
The Tulane University of Louisiana (commonly referred to as Tulane University) is a private research university in New Orleans, Louisiana, United States. Founded as the Medical College of Louisiana in 1834 by a cohort of medical doctors, it b ...
have been developing GM fish for the same purpose.
Several transgenic methods have been used to introduce target DNA into zebrafish for environmental monitoring
Environmental monitoring is the processes and activities that are done to characterize and describe the state of the environment. It is used in the preparation of environmental impact assessments, and in many circumstances in which human activit ...
, including micro-injection, electroporation
Electroporation, also known as electropermeabilization, is a microbiological and biotechnological technique in which an electric field is applied to cells to briefly increase the permeability of the cell membrane. The application of a high-vo ...
, particle gun bombardment, liposome-mediated gene transfer, and sperm-mediated gene transfer. Micro-injection is the most commonly used method to produce transgenic zebrafish as this produces the highest survival rate.
Regulation
The regulation of genetic engineering concerns the approaches taken by governments to assess and manage the risks associated with the development and release of genetically modified crop
Genetically modified crops (GM crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering methods. Plant genomes can be engineered by physical methods or by use of ''Agrobacterium'' for the delivery of se ...
s. There are differences in the regulation of GMOs between countries, with some of the most marked differences occurring between the US and Europe. Regulation varies in a given country depending on the intended use of the products of the genetic engineering. For example, a fish not intended for food use is generally not reviewed by authorities responsible for food safety.
The US FDA guidelines for evaluating transgenic animals define transgenic constructs as "drugs" regulated under the animal drug provisions of the Federal Food and Cosmetic Act. This classification is important for several reasons, including that it places all GM food animal permits under the jurisdiction of the FDA's Center for Veterinary Medicine (CVM) and imposes limits on what information the FDA can release to the public, and furthermore, it avoids a more open food safety review process.
The US states of Washington and Maine have imposed permanent bans on the production of transgenic fish.
Controversy
Critics have objected to use of genetic engineering per se on several grounds, including ethical concerns, ecological concerns (especially about gene flow
In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic variation, genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent ...
), and economic concerns raised by the fact GM techniques and GM organisms are subject to intellectual property law. GMOs also are involved in controversies over GM food with respect to whether using GM fish as food is safe, whether it would exacerbate or cause fish allergies, whether it should be labeled, and whether GM fish and crops are needed to address the world's food needs. These controversies have led to litigation, international trade disputes, and protests, and to restrictive regulation of commercial products in most countries.
There is much doubt among the public about genetically modified animals in general. It is believed that the acceptance of GM fish by the general public is the lowest of all GM animals used for food and pharmaceuticals.
Ethical concerns
In transgenic fast-growing fish genetically modified for growth hormone, the mosaic founder fish vary greatly in their growth rate, reflecting the highly variable proportion and distribution of transgenic cells in their bodies. Fish with these high growth rates (and their progeny) sometimes develop a morphological abnormality similar to acromegaly
Acromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There ...
in humans, exhibiting an enlarged head relative to the body and a bulging operculum. This becomes progressively worse as the fish ages. It can interfere with feeding and may ultimately cause death. According to a study commissioned by Compassion in World Farming, the abnormalities are probably a direct consequence of growth hormone over-expression and have been reported in GM coho salmon, rainbow trout, common carp, channel catfish and loach, but to a lesser extent in Nile tilapia.
In GM coho salmon (''Oncorhynchus kisutch'') there are morphological changes and changed allometry
Allometry (Ancient Greek "other", "measurement") is the study of the relationship of body size to shape, anatomy, physiology and behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in ''On Growth and Form'' and by Jul ...
that lead to reduced swimming abilities. They also exhibit abnormal behaviour such as increased levels of activity with respect to feed-intake and swimming. Several other transgenic fish show decreased swimming ability, likely due to body shape and muscle structure.
Genetically modified triploid fish are more susceptible to temperature stress, have a higher incidence of deformities
(e.g. abnormalities in the eye and lower jaw), and are less aggressive than diploids. Other welfare concerns of GM fish include increased stress under oxygen-deprived conditions caused by increased need for oxygen. It has been shown that deaths due to low levels of oxygen ( hypoxia) in coho salmon are most pronounced in transgenics. It has been suggested the increased sensitivity to hypoxia is caused by the insertion of the extra set of chromosomes requiring a larger nucleus which thereby causes a larger cell overall and a reduction in the surface area to volume ratio of the cell.
Ecological concerns
Transgenic fish are usually developed in strains of near-wild origin. These have an excellent capacity for interbreeding with themselves or wild relatives and therefore possess a significant possibility for establishing themselves in nature should they escape biotic or abiotic containment measures.
A wide range of concerns about the consequences of genetically modified fish escaping have been expressed. For polyploids, these include the degree of sterility, interference with spawning, competing with resources without contributing to subsequent generations. For transgenics, the concerns include characteristics of the genotype, the function of the gene, the type of the gene, potential for causing pleiotropic
Pleiotropy () is a condition in which a single gene or genetic variant influences multiple phenotypic traits. A gene that has such multiple effects is referred to as a ''pleiotropic gene''. Mutations in pleiotropic genes can impact several trait ...
effects, potential for interacting with the remainder of the genome, stability of the construct, ability of the DNA construct A DNA construct is an artificially-designed segment of DNA borne on a Vector (molecular biology), vector that can be used to incorporate genetic material into a target Biological tissue, tissue or Cell (biology), cell. A DNA construct contains a DNA ...
to transpose
In linear algebra, the transpose of a Matrix (mathematics), matrix is an operator which flips a matrix over its diagonal;
that is, it switches the row and column indices of the matrix by producing another matrix, often denoted by (among other ...
within or between genomes.
One study, using relevant life history data from the Japanese medaka ('' Oryzias latipes'') predicts that a transgene introduced into a natural population by a small number of transgenic fish will spread as a result of enhanced mating advantage, but the reduced viability of offspring will cause eventual local extinction of both populations. GM coho salmon show greater risk-taking behaviour and better use of limited food than wild-type fish.
Transgenic coho salmon have enhanced feeding capacity and growth, which can result in a considerably larger body size (>7-fold) compared to non-transgenic salmon. When transgenic and non-transgenic salmon in the same enclosure compete for different levels of food, transgenic individuals consistently outgrow non-transgenic individuals. When food abundance is low, dominant individuals emerge, invariably transgenic, that show strong agonistic and cannibalistic behavior to cohorts and dominate the acquisition of limited food resources. When food availability is low, all groups containing transgenic salmon experience population crashes or complete extinctions, whereas groups containing only non-transgenic salmon have good (72%) survival rates. This has led to the suggestion that these GM fish will survive better than the wild-type when conditions are very poor.
Successful artificial transgenic hybridization between two species of loach (genus ''Misgurnus'') has been reported, yet these species are not known to hybridize naturally.
GloFish were not considered as an environmental threat because they were less fit than normal zebrafish which are unable to establish themselves in the wild in the US.
AquAdvantage salmon
The FDA has said the AquAdvantage Salmon can be safely contained in land-based tanks with little risk of escape into the wild; however, Joe Perry, former chair of the GM panel of the European Food Safety Authority
The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002 ...
, has been quoted as saying "There remain legitimate ecological concerns over the possible consequences if these GM salmon escape to the wild and reproduce, despite FDA assurances over containment and sterility, neither of which can be guaranteed".
AquaBounty indicates their GM salmon can not interbreed with wild fish because they are triploid which makes them sterile
Sterile or sterility may refer to:
*Asepsis, a state of being free from biological contaminants
* Sterile (archaeology), a sediment deposit which contains no evidence of human activity
*Sterilization (microbiology), any process that eliminates or ...
. The possibility of fertile triploids is one of the major short-falls of triploidy being used as a means of bio-containment for transgenic fish. However, it is estimated that 1.1% of eggs remain diploid, and therefore capable of breeding, despite the triploidy process. Others have claimed the sterility process has a failure rate of 5%. With around a million fish in each of the 3,000 Atlantic sites a single failure could result in the release of 1,100 to 5,000 genetically altered fish capable of reproducing. Large scale trials using normal pressure, high pressure, or high pressure plus aged eggs for transgenic coho salmon, give triploidy frequencies of only 99.8%, 97.6%, and 97.0%, respectively. AquaBounty also emphasizes that their GM salmon would not survive wild conditions due to the geographical locations where their research is conducted, as well as the locations of their farms.
The GH transgene can be transmitted via hybridization of GM AquAdvantage Salmon and the closely related wild brown trout
The brown trout (''Salmo trutta'') is a species of salmonid ray-finned fish and the most widely distributed species of the genus ''Salmo'', endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally ...
(''Salmo trutta''). Transgenic hybrids are viable and grow more rapidly than transgenic salmon and other wild-type crosses in conditions emulating a hatchery. In stream mesocosms designed to simulate natural conditions, transgenic hybrids express competitive dominance and suppress the growth of transgenic and non-transgenic salmon by 82% and 54%, respectively. Natural levels of hybridization between these two species can be as high as 41%. Researchers examining this possibility concluded "Ultimately, we suggest that hybridization of transgenic fishes with closely related species represents potential ecological risks for wild populations and a possible route for introgression of a transgene, however low the likelihood, into a new species in nature."
An article in Slate Magazine in December 2012 by Jon Entine, Director of the Genetic Literacy Project, criticized the Obama administration for preventing the publication of the environmental assessment (EA) of the AquAdvantage Salmon, which was completed in April 2012 and which concluded that "the salmon is safe to eat and poses no serious environmental hazards."[Jon Entine for Slate Magazine. Wednesday, Dec. 19, 201]
Is the White House Interfering With a Scientific Review?
/ref> The Slate article said that the publication of the report was stopped "after meetings with the White House, which was debating the political implications of approving the GM salmon, a move likely to infuriate a portion of its base". Within days of the article's publication and less than two months after the election, the FDA released the draft EA and opened the comment period.[Brady Dennis for the Washington Post. December 21, 2012]
Retrieved 2012-12-22.
References
{{DEFAULTSORT:Genetically Modified Fish
Genetically modified organisms
1985 in biotechnology