What I wonder with the blue is if it dies at 45, at what point does it get sluggish enough for the bass to really hammer them? If it is much below 50, the bass themselves maybe sluggish and not wanting to feed. Where as the Mozambique may get sluggish at a slightly warmer temp allowing bass to feed on them better?
Just a thought, I really have no idea...
Interesting thought process.
I would first ask myself "does cold tolerance equate to one extra spawn each year?". If so, then that would probably trump the sluggishness issue in regards to how good a fish is as forage.
