Here’s an interesting little science tidbit.
…farmed males had significantly higher sperm motility and sperm velocity compared to wild males. In addition, wild males had lower sperm longevity and sperm density compared to farmed males. Our results indicate that farming practices may lead to increased sperm performance in Chinook salmon males. While we did not evaluate reproductive success resulting from spawning interactions in the wild, our results do highlight the potential for substantial introgression resulting from male–male competition between farmed and wild Chinook salmon in the wild.
So if farmed Chinook salmon males were to escape and interbreed with the wild population, this could mean that the farmed salmon genetics c0uld affect the wild salmon genetics. This is a concern, of course, but the risks of this are very low since there are only a few companies in B.C. farming Chinook salmon, and not in large amounts.
A real interesting question which this study only touches on is “Why?”
Why do farmed salmon have better sperm than wild salmon?
In humans, at least, sperm motility has been associated with nutrition. It may be that males who eat healthy have more viable sperm than those who do not.
That could mean that sperm in salmon is a sign of health, and in this case, farmed salmon are eating a healthier diet than their wild cousins.