Aquaculture expansion, the real threat of GM salmon? (Updated)

November 25, 2015

One spring years ago we needed a supply teacher for a week at our school and my colleague Elizabeth Docker had a sister visiting who was willing to help out.  Margaret had just completed her  PHD in biology at the University of Guelph.

At the time I was writing a young-adult science fiction novel, and when I discovered our new English teacher specialized in fish, our talk drifted to the semester Margaret and her classmates made salmon fry grow very large by manually destroying the gene in the egg which limits growth.

They used the tiniest pipette they could find, heated it in a bunsen burner until it melted, then twisted it apart until a tiny shard of glass protruded.  With an electron microscope they could carve away at fertilized salmon eggs with this improvised tool and actually damage individual genes.  Apparently the growth-regulating gene is easy to find and shut off.

The salmon fry which hatched grew really big, about 30 times the regular size.

In further research I read a newspaper account of a similar study in New Zealand which ended, not when the test specimens hit 750 kg and took on a scary green hue and huge lumps on their skulls, but when the scientists doing the work realized the things were fertile.

Current news stories have a Canadian aquaculture company raising Chinook salmon with an eel chromosome in fresh-water tanks inland in Panama, but also another company raising double-sized Atlantic salmon in saltwater pens in Nova Scotia.

My friend Dr. Martin Mallet is a geneticist and president of the New Brunswick Shellfish Grower’s Association, so I emailed him an open-ended question on the topic.

So, Dr. Mallet, what do you think?

Martin:  My understanding is that these new GMO salmon are to be sterile females only (though I suppose there must be fertile broodstock somewhere).  

Regardless, my biggest beef with this is not so much with the technology itself as with the production and economic system it embodies. I do not want to see the mistakes of intensive agriculture repeated at sea.

Here’s a similar example: 

Total North American cattle inventory in 2014 was about 100 million head. Peak Buffalo population in North America before we exterminated them? about 100 million. 

So instead of responsibly managing a wild resource, we’ve come up with our own pathetic approximation, a heavily subsidized, unsustainable and polluting one at that. 

How is this different from your oyster operation?  Is it not a feedlot as well?

Martin:  Hardly. We don’t feed the oysters anything once they’re out to sea, so we’re not relying on non-renewable resources for our production, with the exception of gas for the boats and plastic for the grow-out bags and buoys. I’ve not done the formal calculations but I estimate that those costs are largely offset by the carbon oysters capture in their shells. Oyster abundance is historically low, so we’re contributing to restoring some of the lost ecosystem function by adding to the oyster biomass in our bay, with many of the same advantages as natural reefs (filtering capacity, habitat for small fish and crustacean etc..). On top of that, cultured oysters spawn and their offspring are able to colonize available habitat so are much more likely to contribute to wild stocks rather than harm them.

I would argue that the gap between farmed and wild is much much smaller in shellfish culture than in almost any other food production system. If I believed I was doing harm, I wouldn’t be doing it.

Of course, that doesn’t guarantee I’m not doing harm.

My other learned friend Roslyn Dakin, an evolutionary biologist, is completing post-doctorate research on hummingbird flight at the University of British Columbia.

Dr.  Dakin, what’s the view on genetically modified salmon from the west coast?

I like what Martin has to say. I don’t think there’s anything inherently or necessarily bad about genetically modified fish. Same goes with genetically modified plant crops. I’m all for both, if they would solve problems that result from having to fuel so many humans. The classic example is artificial selection – every domesticated animal and plant is the result of genetic modification by many generations of breeders. The question is, do we have the right incentives and regulations to avoid harm by a GM fish industry?

It’s also interesting that just the idea of genetically modified whatever can be so horrifying. The “ick” factor increases the closer you get to us on the evolutionary tree. It’s not hard to sell a GM tomato. But will people buy GM chicken, or GM pork? Also interesting that people in the UK are particularly against genetic modification. Why?

But how about the view in your lab?

The one thing I know is a little bit of the work on wild salmon here showing that their temperature tolerance is remarkably well adapted to the exact natal stream to which they return in the Fraser.
The downside of this is that as the river warms the populations lower in the system will probably be wiped out.  No kidding.

I wonder if the eel-gene allows B.C. salmon to tolerate warmer water?

UPDATE:  9 December, 2015

Dear Rod,

It’s good to hear from you, and I have to say that I’m very surprised that you remembered our discussions after all these years.  I read your blog on GM salmon and, although some of the details are inaccurate (e.g., there is no way that one can manually destroy select genes of interest in salmon eggs while leaving others intact), I’m impressed that you remember the conversations.  I don’t even want to try to figure out how long ago that was!

I hope you’re enjoying retirement.

Best regards, 

Margaret

Margaret F. Docker, Associate Professor

Department of Biological Sciences

University of Manitoba

————————————————-

Oops!  I guess it’s as my friend Robert Ewart says: my memory is rather flexible on the details when a story is at stake.  Now Rob will  undoubtedly chime up with a correction of this quotation from the dimmest echoes  of last Sunday’s dinner.

 

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