Fish from salmon hatcheries are genetically different from wild fish.
That’s the finding of a study done on rainbow trout conducted at Oregon State University (OSU) in collaboration with the Oregon Department of Fisheries and Wildlife. The study found that genetic differences can come on quickly.
“A fish hatchery is a very artificial environment that causes strong natural selection pressures,” said Michael Blouin, a professor of integrative biology in the OSU College of Science. “A concrete box with 50,000 other fish all crowded together and fed pellet food is clearly a lot different than an open stream.”
The study, published in Nature Communications, found that the offspring from wild fish show changes at the DNA-level in a single, passed generation.
According to the study, researchers found more than 700 changed genes between wild fish and the first generation of offspring in hatcheries.
Researchers found the changes occurred in genes related to healing, immunity, and metabolism. In hatcheries, fish are injured more often and disease spreads easier, therefore these genetic differences make the fish more vulnerable.
The next step, say researchers, is to better understand the genetic changes and possibly find a way to make hatchery fish more resilient, like wild fish.