Fwd: Transgenic Fish Coming

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Mon, 15 Dec 2003 15:31:19 GMT

 

Transgenic Fish Coming

press-release

 

The Institute of Science in Society

Science Society Sustainability

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General Enquiries sam

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ISIS Director m.w.ho

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ISIS Press Release 15/12/03

Transgenic Fish Coming

*******************

Prof. Joe Cummins exposes the regulatory vacuum behind the rush for commercial

release of transgenic fish

Sources (http://www.i-sis.org.uk/full/TFCFull.php) for this report are available

in the ISIS members site. Full details here

(http://www.i-sis.org.uk/membership.php)

 

Glofish for the new year

******************

The tiny zebra fish that lives in aquariums, a popular laboratory animal, was

genetically modified to produce a fluorescent red pigment, and is being promoted

for sale as a household aquarium pet, the " glofish " . The glofish caused a stir

in the United States because regulation of such transgenic pets is murky and

none of the major regulatory agencies: FDA, USDA or EPA has been willing to take

the lead in regulating the glofish (even though USDA does deal with pet

animals). The glofish is set to go on sale January 5, 2004 without regulatory

approval.

FDA announced: " Because tropical aquarium fish are not used for food purposes,

they pose no threat to the food supply. There is no evidence that these

genetically engineered zebra danio fish pose any more threat to the environment

than their unmodified counterparts which have long been widely sold in the

United States. In the absence of a clear risk to the public health, the FDA

finds no reason to regulate these particular fish. "

The FDA position that transgenic glofish are substantially equivalent to

unmodified fish is hypothetical and no effort has been made to test the

transgenic fish in contained, but wild-like environments. Fish pigmentation with

" poster " colors is an aphrodisiac to wild fish and may even provide protection

from predators in certain light conditions, or the pigment fluorescence may

signal toxic defence as in the stinging sea anemone from which the glofish

transgene was prepared and in that way discourage predators.

FDA was presumptuous in washing its hands of the regulation of the transgenic

zebra fish, which is likely to become a major pest of warm water areas.

 

Other transgenic fish to follow in droves

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The release of glofish may signal relaxation of the regulation of transgenic

fish now being promoted for commercial release. To ensure that transgenic fish

do not overpower or seriously pollute the gene pool, both promoters and

regulators stress the safety of " sterile " transgenic fish released to bodies of

water. Previously, " sterile " fish are produced using synthetic triploid strains

of fish produced from treatment of eggs pressure or temperature shock and with

sex hormones. As ISIS reported, the sterile triploids were " leaky " and tend to

produce a few fertile progeny, which can establish transgenic populations.

In spite of these problems, the transgenic fish are being promoted as the first

marketable transgenic animals for human consumption. More effort seems to have

been spent on promoting the existing defective transgenic fish than on improving

them so that they can be safely released for commercial production. Muir and

Howard defined conditions under which transgenic fish can cause rapid extinction

to wild fish stock, thus posing extreme risk; but this has been ignored in the

rush to commercialization.

Development of transgenic fish has focused on a few species including salmon,

trout, carp, tilapia and a few others. Salmon and trout are cash crops while the

others primarily provide sources of protein. The salmon nearest to commercial

release is the Atlantic salmon engineered with a pacific salmon growth hormone

driven by the arctic antifreeze promoter gene. The rapid growth of that

transgenic salmon is achieved, not so much by the transgenic growth hormone as

by the antifreeze gene promoter that functions in the cool water desirable for

salmon flavor. The commercial release of transgenic salmon, even in somewhat

contained fish farms, is likely to lead to problems similar to those experienced

in the Atlantic salmon farms of the northwest Pacific. A number of studies

indicate that salmon produced in sea pens escape and breed with native species,

introducing new disease and spreading pollution from the culture pens. These

problems will probably be amplified in the fast growing

transgenic stocks.

Tilapia fish, native to Africa, are cultured world wide as " poor man’s food " ,

second only to carp as warm water food fish, and exceeding the production of

Atlantic salmon (whose market value is twice that of tilapia). Tilapia has been

extensively genetically modified and promoted as a transgenic fish exclusive for

isolated or contained production. Transgenic tilapia, modified with pig

growth-hormone, were three times larger than their non transgenic siblings.

Tilapia genetically modified with human insulin grew faster than non-transgenic

siblings, and could also serve as a source of islet cells for transplantation to

human subjects. Trout growth hormone was used to produce transgenic carp with

improved dressing properties. Such transgenic carp are recommended for

production in earthen ponds.

Giant mud loach was produced by linking the mud loach growth hormone with its

actin promoter. These giant fish are not, technically speaking, " transgenic " , as

they contain no foreign genes even though the inserted construct is artificial,

and pose a paradox for regulators.

Silk moth genes were introduced into Medaka fish to create resistance to

bacterial pathogens. Some commercially desirable fish and crustaceans have been

difficult to genetically engineer because embryonic tissue is difficult to

manipulate. But it has been found that the parental gonads of such animals could

be modified using replication defective pantropic retroviral vectors. Pantropic

vectors can transform an array of species they are modified forms of the Moloney

mouse leukemia virus used extensively in gene therapy. Such vectors have proven

useful in modification of a range of edible marine animals including mollusks.

Animals produced using modified mammalian leukemia viruses will require

extensive testing and long-term evaluation prior to release for human

consumption. This is particularly important in view of the leukemia cases found

among the handful of successes in human gene therapy, which were done with a

retroviral vector (see " Gene therapy risks exposed " , Science in

Society 19).

 

Contained cultures of transgenic fish

****************************

The current generation of transgenic fish has not passed the test of complete

sterility if released or escaped to the environment. Fish production in inland

earthen ponds may prove acceptable for contained transgenic fish culture. But

such facilities should be provided with fail-safe destruction of the pond

animals in the event of flooding and adequate protection from theft. Pond

commercial culture is effective for carp and tilapia, but more difficult with

salmon and trout. Currently, pond culture is suitable for carp and tilapia

because the fish are vegetarians, carnivorous salmon and trout depend on a diet

of fish and fishmeal but the worldwide stock of feed fish has diminished and

suitable vegetable meat substitutes must be found. Atlantic salmon (as typical

cold water carnivores) cannot thrive on a diet of rapeseed oils but the fish can

achieve maturity if finished with fish oils at least 20 weeks near the end of

their maturity cycle. GM oil rape seed with enhanced production of

long chain fatty acids are proposed to serve as feed for pond cultured fish.

And glyphosate-tolerant GM canola meal has been pronounced substantially

equivalent to non-GM canola as feed for rainbow trout.

Aquaculture can help feed the world without diminishing ocean resources, but

premature releases of transgenic fish stocks will do more harm than good. Bad

decisions have plagued aquaculture, resulting in pollution and extensive damage

to native stocks. International agencies such as the World Bank, the

International Development Bank and the Food and Agriculture Organization of the

United Nations have created harm by ill- advised projects that led to damage to

native resources and pollution. Scientists Julio E. Pérez and Mauro Nirchio of

Venezuala along with Juan A. Gomez of Panama commented in Nature: " However, if

the aquaculture industry is going to reduce the pressure on wild fish stocks and

provide food for the world’s growing population, substantial changes must be

made by governments, the private sector and international funding agencies. They

must protect coastal ecosystems; promote research and development of native

species; and encourage farming of low-trophic-level fish —

those low on the food chain. International technical funding agencies can exert

great influence in changing practices " . Without such constructive thinking, the

aquaculture industry poses a threat, not only to ocean fisheries but also to

itself.

 

 

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http://www.i-sis.org.uk/TFC.php

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General Enquiries sam

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