There are more than seven hundred genetic variations between wild salmon and salmon raised in hatcheries, a new study suggests.
The Oregon Department of Fisheries and Wildlife, along with researchers at Oregon State University, have found that hatchery-born salmon can become extremely different from their cousins in the wild within just one generation.
Mark Christie, lead author of the study and a postdoctoral research associate in the Department of Zoology at Oregon State University, said that hatchery-born salmon had a large number of genes involved in wound healing, immunity, and metabolism. In the earliest stages of domestication, the animals usually adapt to highly crowded conditions, Christie noted.
In the new study – published Wednesday (Feb. 17) in the journal Nature Communications – the researchers found DNA evidence that shows the differences between hatchery-born salmon and wild salmon. Researchers looked at wild salmon and the offspring of first-generation hatchery-raised salmon, and compared the two. The results showed that there were 736 genetic differences between the two types of fishes.
Michael Blouin, an author of the study and a professor of integrative biology at the Oregon State University College of Science, the new findings settle the question of whether fishes raised in a hatchery can become genetically different even after just one generation of domestication.
The next step is to find out which of the traits are under strong selection in the fish hatchery. There are strong natural selection pressures in a fish hatchery, caused by the extremely artificial environment – salmon are usually packed gill-to-gill, making it a breeding ground for contamination and disease, Dr. Blouin explained.
Some conservationists are worried that the diseases could be spreads to the salmon population in the wild. However, researchers say that the new study may help improve fish hatcheries so that the salmon they produce are more similar to salmon in the wild. This could potentially help recover the wild salmon population, according to the researchers.
Dr. Blouin said that further studies could help shed some light on which traits of salmon are favoured in fish hatcheries. Changing the way in which hatchery salmon are raised, might reduce the selection pressure on the fish, Blouin explained.
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