Quote Originally Posted by Betty Hiner View Post
Darn ... forgot to add to that last post.

How does the trouts DNA get changed? Is there a mutation caused by hatchery practices that is inherited?
How these hatchery trout change is very complicated. The general public believes that the only way animals can change the way they look and behave is by changing the DNA genetic code. This is NOT true. There are many ways. There is DNA, RNA, and genetic expression. DNA is nucleus. RNA is better explained below:

http://en.wikipedia.org/wiki/RNA

Genetic expression is which genes are turned on or off. RNA codes for proteins and enzymes, and proteins and enzymes can control behavior.

So it is possible to change behavior without changing the DNA. For example, there are instances of hatchery trout that do know how to spawn. They do not express the gene for reproduction from making redds to choosing mates. So they may still have the DNA for that controls spawning but it is not expressed normally. When multiple generations of trout are raised in a raceway without the need to spawn, they can lose that ability.

Hatchery trout are raised not only to tolerate but to embrace crowding and aggression when feeding. That behavior is rewarded in a hatchery, and so fish that exhibit that characteristic are more likely to survive.

The hatchery environment molds the behavior of the fish using the biologic systems of DNA, RNA, and genetic expression to change the behavior of the fish so that it adapts to its environment which is a fish hatchery. Unfortunately, this selects for behavior that is a survival disadvantage in the wild.

Here is a recent article from The Drake Magazine on hatchery steelhead vs wild steelhead in Oregon and Washington:

OREGON AND WASHINGTON FACE THEIR FUTURE

The state fish and game departments for Washington and Oregon both face a major dilemma: how to adequately protect what remains of their wild steelhead, while also continuing to produce hatchery steelhead for the many anglers who like to bring one home for dinner.

Achieving both of these goals has never been easy, but it's become even more difficult lately, with a growing mountain of evidence now showing that, in the vast majority of cases, hatchery steelhead once thought to help or enhance wild steelhead numbers do precisely the opposite.

The result has been an increasingly bitter battle playing out between the two user groups, with wild fish advocates on one side, hatchery advocates on the other, and state fisheries personnel often stuck in the middle.

http://www.drakemag.com/back-issues/...mag+(DrakeMag)