"fishing" I believe is a taught habit from mother to cubs. I doubt that the energy expended isn't worth the small amount of protein gained. Where there are thousands of fish in a single pool like in Salmon runs the energy expended is worth it. I have saw a bear on Chilhowee pass by a fish carcass (albeit was carp) to feed on wild cherries. A bear can lay in a single oak tree and burn almost zero calories "lapping" acorns. I know that a bear just can't pass up a yellow jacket nest.
Deer, hogs, and bear love diesel fuel too. I guess it's the sulpfur in it. We once had a tractor parked in a field and the deer licked the paint to a shine but, only where the diesel had over flowed on it over the years.