I sincerely enjoy both, and do all as much as I can.
But per the OP's question - if I could only do 1 for the rest of my life: I would have to choose fishing.
Because
1) I will get more chances to fish than to hunt. Both because of finances, access, and seasons.
2) I believe I will be able to spend more time with my family (kids, someday grandkids) fishing than hunting. Even people who aren't fishermen will come fishing with grandpa for a few hours.