News: Aug 25, 2009
Fast growing transgenic fish can revolutionise commercial fish farming and relieve the pressure on overexploited fish stocks. But what happens in the natural environment if transgenic fish escape? Researchers at the University of Gothenburg have studied transgenic fish on behalf of the EU and are urging caution:
-Until further notice transgenic fish should be bred in closed systems on land, says Fredrik Sundström at the Department of Zoology, University of Gothenburg.
By furnishing fish with genes from other organisms, so-called transgenes, researchers have succeeded in producing fish that grow considerably faster or are more resistant to diseases. Fish can also be modified to cope better with cold, which facilitates breeding in colder conditions. There are major benefits for commercial fish farming as transgenic fish are expected to deliver higher production and better yields. However, transgenic fish
can might (*) also entail risks and undesirable effects on the natural environment.
For example, transgenic fish
can might prove to (*) be more resistant to environmental toxins, which could may (*) entail the accumulation of toxins that ultimately end up in consumers. There are also misgivings that the higher level of growth hormone in the fish can may (*) affect people. Researchers at the University of Gothenburg have therefore been commissioned by the EU to study the environmental effects of GMO (genetically modified organisms) within fish farming. The results of the studies show that the genetically modified fish should be treated with great care.
Fredrik Sundström, PhD at the Department of Zoology, has studied transgenic salmon and rainbow trout to ascertain what ecological risks they might constitute for the natural environment. The study, which simulated escapes in a laboratory environment, shows that transgenic fish have a considerably greater effect on the natural environment than hatchery-reared non-transgenic fish when they escape. For example, genetically modified fish survive better when there is a shortage of food, and benefit more than non-transgenic fish from increasing water temperatures.
-It is probably due to the fact that genetically modified fish have a greater ability to compete and are better at converting food, says Fredrik Sundström.
If transgenic fish become established in natural stocks they would be able to outcompete the natural breeds. However, conducting studies in a laboratory environment that imitates nature is complicated, which makes it difficult to predict how escaped transgenic fish affect the natural environment. Fredrik Sundström's conclusion is that international consensus is required before commercial farming can be permitted, and that a precautionary principle must be applied.
-One option is to farm the transgenic fish on land, which would make escape impossible. At least fertile fish should be kept in a closed system, says Fredrik Sundström.
As of yet no country has permitted commercial farming of transgenic fish, but several applications for such operations are under consideration by authorities in both the USA and the EU.
Summary of the report: Ecological risk-assessments of transgenic salmon
Fredrik Sundström, Department of Zoology, University of Gothenburg
+46 (0)734-084 922
Caption: One of the locations where Fredrik Sundström's studies were conducted was in an artificial stream where microchips were used to documented the movements of the fish. Photo: Lars-Erik Sundström.
The Ecological Risk Assessment of Transgenic Salmon project commenced in May 2005 and concluded in April 2009. It has been conducted at the Centre for Aquaculture and Environmental Research in Vancouver, Canada on behalf of the EU, the Swedish Research Council Formas and the University of Gothenburg. Coordinator in Sweden is Professor Jörgen Johnsson, Department of Zoology.
FACTS ABOUT TRANSGENIC FISH
Transgenic fish are created by transferring genes to fish from other species, including human beings. The gene selected is propagated using bacteria and then isolated, purified and introduced into the eggs of the host fish by microinjection. The genes transferred contain a DNA sequence with codes for the required characteristic. Hitherto researchers have genetically modified some twenty fish species, including carp, salmon and catfish.
(*) Note: We have been notified to the fact that the translation of the press release from Swedish into English have some flaws when describing the contributory cause for the study, all related to the small Swedish word “kan” which has a wide meaning.
Since it is of utmost importance to us that the English version is accurate, we have made some minor changes in the text on August 17 2010. The changes made are clearly visible in the text above.
We are sorry for the inconvenience this may have caused.
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In case of doubt or confusion, the Swedish version of this press release takes precedence.