Evidence have been piling up that fish grown in the wild is very different from those raised in a hatchery. A new research suggests that hatcheries produce genetic changes in salmon making them far different in many ways compare to wild ones.

Researchers from Oregon State University found genetic evidence that wild and hatchery steelhead trouts are different at the DNA level and this difference happens at a surprising speed. This difference can actually be passed onto next generations.

Published in the journal Nature Communications, the study shows that fishes that were raised in hatcheries produced offspring with unique genetic make-up compared to the offspring of wild fish. The fish born in the hatchery showed differences in the expression of 700 genes.

Inbreeding And Genetic Changes

A fish hatchery is a place for artificial breeding, hatching and rearing of animals like fishes. With fish stocks depleted in many parts of the world, fish hatcheries boomed in the last couple of decades. There are, however, associated problems linked with aquaculture.

One problem that emerges is inbreeding. With only a small number of stocks in hatcheries, inbreeding can potentially create unhealthy and malformed populations.

"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.

"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 researchers are certain on what traits are being expressed by hatcher fish, but some are associated the immune system and tissue regeneration. This might explain why fishes in the hatchery are more prone to disease outbreaks, metabolism and wounds.

The study sheds light on hatcheries and their effects to fishes. If these genetic changes are better understood, it can give valuable information on measures to address the problem. It could open doors in exploring other ways of raising fishes in hatcheries that could reduce detrimental genetic changes.

Difference Between Hatchery And Wild Salmon

Streams and hatcheries are the same in the sense that they provide necessary conditions for young salmon fishes to live like food, space, water and shelter. However, years of culturing under artificial conditions created changes to hatchery fish.

Hatchery fishes are used to hand-feeding or just waiting for food to arrive while wild fishes hunt for their food. Hatcheries provide shelter for fish while wild fish rely on natural shelter in streams. Wild fish are known to survive and withstand the severities of the natural environment long enough to reproduce. 

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