Strange to have an article about salmon farming drawbacks without mentioning escaped salmons polluting the wild salmon population. There has been a strong decrease in wild salmon as they lose the ability to migrate back up the river to lay their eggs due to breeding with escaped farming salmon.
I suppose natural selection will act on those salmon that can't reproduce.
That is... unintuitive. Wouldn't the escaped salmon have to be able to get back upstream enough to where the wild salmon are laying/milting?
I think the idea is that the migration instinct passed down by wild salmon is an epigenetic heritable trait. This trait is strongly selected for in wild salmon populations, but not in farmed populations. The constant influx of this maladaptive trait into the wild population is leading to an overall decrease in the ability of the wild population to successfully propagate.
They’ve bred more docile salmon, according to the article. Getting that DNA into wild populations would be problematic I’d imagine.
Don’t forget the dams and the humpback salmon.