Salmon Hatcheries Cause Changes In Fish DNA

Posted: Feb 18 2016, 8:02am CST | by , Updated: Feb 18 2016, 8:06am CST, in News | Latest Science News


Salmon Hatcheries Cause Changes in Fish DNA
These are steelhead trout drift in an Oregon stream. Photo by John McMillan, courtesy of Oregon State University

It has been found that salmon hatcheries may cause profound changes in fish DNA.

Some research into trout in Oregon lend credence to the view that fish in the wild and those in hatcheries have vastly different DNA. Moreover, with the passage of time, these fish drift even further apart from each other.

The study got published in a journal. After a single generation, both wild fish and hatchery fish differ as regards 700 of their genes. These genetic mutations at the level of the DNA got transmitted to the offspring. 

Oregon State University was the source of the experiment that proved this initial hypothesis without a shadow of doubt. The Fisheries and Wildlife Department was collaborating with the university staff on this one too.

For now at least the case is closed on the basic difference between hatchery fish and wild fish. Issues of survival rates and reproductive success in both types of fish have plagued scientists since times immemorial.

It is acclimatization to hatchery conditions that changes the DNA of the fish. Otherwise it would have remained constant in the wild and natural environment.  

The differences between the genetic materials of fish in a natural setting and in an artificial one are obvious. They are very vast and the heritability is almost 100%.

The problem is that in a confined hatchery the population pressures and natural selection get all mixed up. Imagine, a single box-like environment that has 50,000 fish in it that are cheek by jowl and fed artificial food.

This is clearly worlds apart from a clear stream with ample room. All the genetic changes  were not apparent in the beginning. Some of the fish were responding to the novel situation by changing their genes on a fundamental level. 

Such changes as alterations in wound healing, immune system function and metabolic pathways were noticable. We haven’t received the full picture just yet. The scientists are still working on it.

The early milieu of the salmon is probably one that is crowded beyond belief. Otherwise what else could account for the biological symptoms that arise with the passage of time.

A single generation is all it takes. Evolutionary processes seem to speed up ahead of time here. It is an amazing find since the changes in the fish are an unbelievable fact in such a limited time span. As they say though: seeing is believing.  

The research was published in Nature Communications.

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<a href="/latest_stories/all/all/20" rel="author">Sumayah Aamir</a>
Sumayah Aamir (Google+) has deep experience in analyzing the latest trends.




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