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article imageHatchery-raised salmon are genetically different from wild salmon

By Karen Graham     Feb 20, 2016 in Environment
Hatchery raised-salmon bred to help bolster wild stocks in British Columbia become genetically different than their wild counterparts in only one generation, according to a study by researchers at Oregon State University.
The study tracked the offspring of Hood River hatchery-raised steelhead trout, Oncorhynchus mykiss, and compared their genetic profile to that of wild steelhead in the same river system, reports Maine News Online.
It has been known for some time that the offspring of wild and hatchery-raised salmon are less adept at surviving in the wild, having a negative effect on the health of wild populations. The question researchers asked was why then do hatcheries raise fish that are less likely to survive in the wild?
"What we found is that when you compare the fish that had two wild parents with those that had two hatchery parents, we see hundreds of genes with different activity," researcher and lead author Michael Blouin told On The Coast guest host Michelle Eliot. Actually, the team found over 700 gene variations.
Blouin said many of the changed genes were involved in wound repair, metabolism and immune function, suggesting these differences were related to the earliest stages of domestication where the fry have to adapt to crowded conditions. Blouin said he wonders "why that would cause a correlated ability to do worse in the wild is not clear. Maybe it's an energetic thing."
The study seems to answer the question of which traits are under strong selection in hatcheries, and which hatchery conditions affect the selection the most. One primary suggestion to come out of the study would be to raise hatchery fish, regardless of the species, in as near to natural conditions in the wild as possible, reports CBC News Canada.
“A fish hatchery is a very artificial environment that causes strong natural selection pressures,” Blouin explained in a statement. The survival rate of salmon raised in hatcheries and released into the wild to replenish wild populations is impacted negatively when in artificial fish farms, salmons are packed gill-to-gill. Such conditions make the salmon in hatcheries vulnerable to disease and contamination and, thus, the risk to survival.
The study, "A single generation of domestication heritably alters the expression of hundreds of genes," was published in the journal, Nature Communications on February 17, 2016.
More about Wild salmon, genetic variations, metabolism and reproduction, not as healthy, hatcheryraised salmon
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