10-Year Study Shows Wild Salmon Runs May Not Survive Fish Farming

[hatrack]

Farm threat to wild salmon
By Helen Briggs
BBC News Online science reporter

Repeated escapes of farmed salmon could drive endangered populations of wild Atlantic salmon to extinction, say scientists in the British Isles.

"There has been concern over the past decade that domesticated salmon are breeding with native salmon, changing the genetic make-up of the fish and damaging their ability to survive in the natural environment. Until now, there has been little direct scientific evidence but, according to a report published in the journal Royal Society Proceedings B, the fears of environmentalists may be justified.

In a 10-year study, researchers from Ireland, Northern Island and Scotland, found that wild salmon were vulnerable to extinction because of genetic and competitive pressures from farmed fish.

Experiments with wild and farmed salmon hybrids in fresh and marine water showed that the offspring of fish that had interbred had a much lower survival rate - some 70% of the fish died in the first few weeks of life.

Overall, farmed salmon were much less successful at surviving in the wild compared with native salmon and were unlikely to return to rivers to spawn. However, they grew quicker than wild salmon and the ones that did survive displaced many of their wild cousins from the rivers."

EDIT

http://news.bbc.co.uk/2/hi/science/nature/3195062.stm

[mainegreen]

1. Its the same here in Maine

http://www.mindfully.org/Water/2003/Farmed-Salmon-Threaten13jun03.htm

[sandlapper]

2. Is this logic really valid?

"Experiments with wild and farmed salmon hybrids in fresh and marine water showed that the offspring of fish that had interbred had a much lower survival rate - some 70% of the fish died in the first few weeks of life. "

As I read this the implication is that the 30% that survived would not be capable of sustaining the "wild/farmed hybrids". Isn't this making a rather extreme assumption that the survivors are no more competent in the "wild" than were the original "hybrids". This seems to fly in the face of experience with other feral species. Second or third generation feral cats or dogs are highly successful competitors with their "wild" cousins. Why would salmon be any different? Most especially when fish do not have any of the training /nurturing habits of mammalian counterparts.

What after all would you call a second generation "wild/farmed hybrid" that had never been in anything but open ocean or lake? Wouldn't the term be "wild"?

The semantics are very confusing!