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Genetically Altered Salmon Grow Twice As Fast And Could Be Twice As Toxic

That juicy salmon steak on your plate may look the same as ever, but the fish has spent about half the growing time compared with its original farmed ancestor which may lead to a host of problems.

Today's Atlantic salmon reaches market size "about twice as fast as those the Norwegians farmed in 1970," according to Eric Hallerman, a fish geneticist at Virginia Tech. And now a new transgenic salmon may once again double growth speeds to four times the original rate.

The latest salmon, created by AquaBounty Technologies, could become the first genetically engineered animal to be approved by the U.S. Food and Drug Administration as food. Both genetically modified fish and farmed fish represent the toxic future of food, many experts now say.

A series of recent FDA panel hearings brought geneticists and fishery managers to the table, along with consumer and environmental advocates in Rockville, Md. The public events aimed to air any concerns about the genetically modified salmon – preferably before they led to alarmed dinner-table discussions in U.S. homes. (Too late, the beast has already been dubbed "frankenfish".)

One expert suggested delaying any approval because of incomplete studies on how such rapid growth affects the health of the fish.

"The FDA said it would continue to monitor how well the fish perform over time," said Craig Altier, a molecular biologist at Cornell University. "I suggested the time to do it would be now, before approval."

The main concerns seem to involve animal welfare rather than direct risks to human health, according to Altier, who is also a member of the FDA's Veterinary Medicine Advisory Committee.

Weighing the risks

AquaBounty's Atlantic salmon has additional DNA from both Pacific Chinook salmon and an eel-like fish, which allows it to keep pumping out growth hormone year-round. So while the modified salmon doesn't grow bigger than normal salmon, its hyper-growth rate means that it can go to market sooner

Concerns remain if some of the studies completed by the FDA had been large enough. Altier pointed out that AquaBounty's study on the health of the fish involved groups of just three to six fish, for a total of 120 in all – a puny sampling compared with the hundreds of thousands of salmon that could have been recruited.

Even though routine, the weeding-out of abnormal fish could skew the study results, essentially leaving only positive results to report, albeit unintentionally, Altier said.

"They actually removed the ones that you might worry about," Altier explained. "The numbers that were removed were small, but it gave us great concern."

Many experts argue that farm-raised salmon contain significantly more dioxins and other potentially cancer-causing pollutants than do salmon caught in the wild, says a major study that tested contaminants in fish bought around the world. Salmon farmed in Northern Europe had the most contaminants, followed by North America and Chile. The study blames the feed used on fish farms for concentrating the ocean pollutants.

Marcus Sheldon who operates a conventional fish farm in B.C says that genetically modified salmon could accelerate toxicity levels. "That's just not natural," said Sheldon. "Twice the growth is likely twice the toxicity as well if you consider artifically inflated hormonal levels which we don't know the long term effects of."

Salmon Farm Facts

- A salmon farm is likely to hold 500,000 to 750,000 fish in an area the size of four football fields

- The biomass of farmed salmon at one farm site can equal 480 Indian bull elephants - that is 2,400 tonnes of eating, excreting livestock

- Salmon are carnivores. On average it takes two to five kilograms of wild fish (used in feed) to produce one kilogram of farmed salmon

- In one study, over a billion sea lice eggs were produced by just twelve farms in a two week period preceding the out-migration of wild juvenile salmon.

- Infection with one to three sea lice can kill a wild juvenile pink salmon.

- Canada and Chile are the two primary sources of farmed salmon for American consumers.

- Two-thirds of the salmon consumed by Americans is farm-raised.

Taking security measures

AquaBounty plans to grow only female fish at two indoor facilities. A smaller breeding facility at Prince Edward Island, Canada, would hold fertile salmon that provided the eggs.

High pressure applied to the eggs renders the resulting offspring sterile with around a 99 percent effectiveness rate, according to Hallerman of Virginia Tech, who made a presentation at the FDA hearings.

The sterile, all-female offspring would grow up at a separate isolated facility in Panama. Their self-contained tanks would use re-circulated water.

Even if Atlantic salmon somehow escaped the Panama facility, they would not fare well in the warm water rivers, Hallerman explained. But a bigger risk could come from someone trying to break into the Prince Edward Island facility and stealing even one fertile fish.

"One area where I thought they could have had more detail is how they would secure the facility against human intrusion or theft," Hallerman said in a phone interview.

Moving forward

For now, the FDA has told AquaBounty to keep collecting health data on its genetically modified fish for an indefinite period of time. A decision by the federal agency on whether the fish can go to market could come within the next several weeks or months.

Other examples of transgenic fish have already entered the development pipeline. But whether or not the fish themselves come from genetic tinkering, experts agree that the world has already come to rely upon artificial methods of raising fish through aquaculture – especially as wild fish populations plummet due to overfishing.

"The real challenge is doing aquaculture in a sustainable way," Altier said.

Aquaculture represented just 4 percent of the world's fishery products during the late 1970s, when Hallerman seriously began his professional career. Now the amount of farmed fish makes up 50 percent of fish consumed globally.

Creutzfeldt Jakob disease

Three U.S. scientists are concern about the potential of people contracting Creutzfeldt Jakob disease -- the human form of "mad cow disease" -- from eating farmed fish who are fed byproducts rendered from cows.

Mad cow disease, also called bovine spongiform encephalopathy is a fatal brain disease in cattle, which scientists believe can cause Creutzfeldt Jakob disease in humans who eat infected cow parts. The infectious particles eat away at the brain, leaving tiny sponge-like holes. There is no treatment available and death always follows.

In the latest issue of the Journal of Alzheimer's Disease, Dr. Robert P. Friedland, a neurologist at University of Louisville in Kentucky and colleagues suggest that farmed fish fed contaminated cow parts could transmit Creutzfeldt Jakob disease.

The scientists want government regulators to ban feeding cow meat or bone meal to fish until the safety of this common practice can be confirmed.


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