It is also noticed that Golden trout are more aggressive and stay higher in the water....one theory for both these "traits" is that the bright color makes them more easily seen by predator and prey alike...They stay higher to avoid predation from fish,but making them vulnerable to birds of prey...they are more agressive, because prey see them and avoid them more easily...thus, they are hungrier and more agressively chase food.
If there were wild, reproducing populations of golden trout I might be able to think they ended up being aggressive for those reasons through natural selection. But, since these trout have spent their lives in a hatchery being fed and not preyed on, I don't know if that's very likely. I don't think that the trout are aware that they're yellow and need to be more aggressive because of it but maybe after being in a natural setting for a while they'd become more aggressive towards forage and therefore lures.
