Hatchery fish results in genetic mutations study finds

A new study indicates that fish bred in hatcheries result in genetic alterations, as reported in Tech Times. The research, conducted at Oregon State University, pointed to evidence that wild and hatchery steelhead trout have different DNA levels, which are passed on to progeny. The study was published in the journal Nature Communications and documents mounting evidence that fish raised in synthetic environments showed differences in 700 genes.

Hatcheries have swelled in the last couple decades to compensate for depleted fish stocks in many parts of the world. But scientists have been discovering the side-effects of artificial breeding. One consequence is inbreeding, arising from small stock populations in incubators creating malformed offspring. “A fish hatchery is a very artificial environment that causes strong natural selection pressures,” said Professor Michael Blouin of the integrative biology in the OSU College of Science. He adds, “A concrete box with 50,000 other fish all crowded together and fed pellet food is clearly a lot different than an open stream.”

Researchers have targeted the dysfunctional traits hatchery fish produce, but some are embedded in the immune system and tissue regeneration, which explains why posterity is more prone to disease outbreaks, metabolism deficiencies and wounds. If scientists can pinpoint where genetic mutation happens the problem can be addressed and could lead to other ways of breeding fish populations without the deformities.

Both natural aquatic environments and hatcheries provide necessary conditions for the offspring to develop. Years of culturing under synthetic conditions results in mutations. Incubated fish populations are accustomed to hand-feeding, whereas wild fish hunt for their food and have naturally adapted to the environment’s dangers.