More Transgenic Fish Coming

Date Posted: 12/15/2003
Subject: Transgenic Fish Coming
Posted By: press-release@i-sis.org.uk
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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
*******************************
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 man¹s
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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