I would think that, generally, a population of a species has a genetic makeup that reflects the behaviour that selection pressure has pushed them into, rather than having a behaviour that is dictated to them by their genetic makeup. However, time is a factor. Evolution can only act as quickly as the generations and the variations in physical characteristics and behaviour patterns allows.
Yes, no and maybe!
After all there are the big sea trout of Currane in SW Ireland which are far bigger on average than those all the close by surrounding fisheries. The Currane smolts are going into the same seas as all the other local rivers but are the only ones going further and growing bigger.
There are two genetically different strains of "sea trout", one a fast growing short lived (and more inclined to travel) and one a slow growing long lived.
In the same way there is a Ferox gene. This was in part proved in Norway when non ferox trout were stocked into hydro lakes full of charr but failed to feed on them, it just wasn't in them.
I have read that one of the problems for Atlantic salmon is that global warming has pushed their food supply further north faster than their behaviour patterns can keep up with.
And yet this year salmon have returned from the sea in numbers that everyone is telling me are similar to those of twenty or thirty years ago. An odd year with good feeding further south or something Covid lockdown related?
Anyone seen a net marked salmon this year? I've had the returns for over 500 fish come through my hands this year and not one mention of a net marked fish. Makes you think.