Sunday, June 12, 2011
WHEN IS A SALMON'S DADDY ALSO IT'S MOMMY?
When it is a B.C. genetically modified salmon. No such thing? Oh, but there is, and has been, for some time. In fact, I first heard of genetically modified fish fifteen years ago when I was living in Clayoquot Sound, on down from a fish farm. A young female worker at the fish farm told me one day that she was quitting her job because they were using sex hormones to change the sex of the fish. She was horrified. “It’s unnatural!” she shrieked.
At the time, I took this with a grain of salt. I didn’t know this woman very well, and her story didn’t wash. Why would the farms want to change the sex of their fish? It didn’t make sense. Not long after, I moved away from the Sound for various reasons, but never quite forgot the young woman and her story.
Gradually I began to accumulate hints of why fish farms might want to have sex changed fish, and/or their off-spring, in their pens. It’s because up to twenty per cent of male salmon “jack early” that is, come to maturity early. The female fish aren’t ready to engage (and will be killed before they are) so these males die. They are a financial loss to the farm. So the farms are looking for a way to elimate the males in their pens.
And guess what? There is a way. Several of them, in fact. With sex hormones. In a paper entitled Hormones and Sex Control in Fish with Particular Emphasis on Salmon from the Department of Fisheries and Oceans at the West Vancouver Laboratory, one way fish farmers can get all female fish is described. They simply immerse some female fry in testosterone which effectively turns them into males, that is, the treated females when grown produce sperm, act as males and are able to fertilize the eggs of normal females. However, because the hormonally altered parent is still genetically female, her sperm will contain predominately xx (female) chromosomes instead of equal amounts of xx and xy (male) chromosomes. An alternate method is simply to treat the male fish directly with estrogens to turn them into females.
Other experiments are also taking place on fish in BC, including fresh water fish. One is called “induced triploid fish” which means, without going into the details of the manipulation of the fish, that they are rendered sterile. A kind of eternal youth for the fish (they don’t go into reproductive mode) which means their flesh stays firm for the tourists palate. Isn’t that lovely?
Currently, fifty per cent of the small lakes in BC are stocked with these “induced triploid fish” (Freshwater Fisheries of BC.) How can it happen that the wild fish that used to bless us with their abundance and the natural sweetness of their flesh have become sex changed and sterile? Where are BC’s investigative reporters? Are all of them in Boston?