Its big. It grows 4 to 11 times faster than its ordinary
relatives. And its coming to a plate near you as soon as its
developers can get approval.
Its a transgenic salmon with a gene from a cold-water species
so that it continues to grow during cold periods. It may not grow
any bigger than existing fish, but it reaches its commercial weight
Growth rates have already been improved by 10-23 percent
per generation simply through selective breeding, says Devin
Bartley, FAOs fish genetics expert. Modifying genes
can intensify the process. The first impacts will be commercial,
probably in developed countries. But in the end, modified fish may
increase food security.
Aquaculture has expanded massively in the last 25 years, providing
a wonderful new source of protein. Most of the progress has been
in developing countries using conventional animal breeding technologies.
New research is on transgenic varieties of species that are widely
farmed in the developing world for example, tilapia and carps.
Will the fish be safe to eat?
I think the technology is less important than the end result,
says Dr Bartley. Thorough testing is crucial for all novel
foods, but in the end, food safety should be assessed on the basis
of whats actually on your plate, not how it got there.
The call of the wild
But the environmental implications of genetically modified fish
are even more pressing than those of terrestrial animals. Because
the life cycles of fish are so much shorter and they are so much
more numerous, genetically modified fish would have a faster impact.
And farmed fish dont always stay where theyre meant
to. About 30 percent of the salmon in Norways rivers are escaped
farm fish, and in some regions the escape rate is higher. In the
Canadian province of New Brunswick, around 33 percent of salmon
are thought to be escapees. Farmed fish in the wild are already
associated with the spread of pests and diseases such as sea lice.
But the escape of transgenic salmon and other farmed transgenic
fish would raise more troubling questions.
Being bred for the plate, they probably wont survive
in the wild but what if they were to survive just long
enough to breed? Their soft characteristics could
enter the wild population, compromising their descendants
ability to survive.
Transgenic fish may be stronger, not weaker, and may compete
for food, reducing the wild population and then they
could die out because of their inability to breed.
Transgenic fish are already being bred for resistance to disease
and pests. In the wild, resistant fish could act as hosts for
organisms that would normally kill them. Those organisms could
then attack real wild fish.
Reducing the risks
These risks will be reduced through insertion of an extra set of
chromosomes to prevent transgenic fish from breeding. But a very
small percentage may accidentally have the normal two sets of chromosomes,
allowing them to reproduce.
However, some of these dangers could also arise from any breeding
method that produces a fish different from wild species. Moreover,
although there are now legally binding international standards concerning
genetically modified organisms (the Cartagena Protocol see
links), alien species seem to get less attention although
there has been more proven damage from such species.
Genetically modified fish are a real prospect. The fast-growing
salmon awaits approval from the US Food and Drug Administration
and the Canadian Department of Fisheries and Oceans. Further ahead,
Canadian scientists are working on tilapia that will produce insulin
for diabetics, while scientists elsewhere are developing tilapia
with human growth hormone and disease-resistant shrimp.
Meanwhile, fish genes are finding their way onto dry land. The
anti-freeze protein gene from the Arctic flatfish used in the Canadian
salmon is being transferred to food crops. In Britain a salmon gene
that controls calcium loss is being transferred into rabbits. This
work is experimental, but its clear that fish are caught up
in the gene revolution in a big way.