Paper mentions fisher preference for larger prey ("ornamental"); I think another factor, not mentioned, may be our innate protectiveness towards juveniles (children, babies).
Implied but not mentioned is that the evolutionary pressure of predation on juveniles should act more quickly than on adults (because more time needs to have passed to reach adulthood; slower iteration).
Hmmm, I haven't read the whole study but in the beginning it says "We focus on adult prey because hunters and fishers overwhelmingly target adults (18)." I mostly speak about my family's patterns, inculcated by my father, but we practice "too small, throw it back" or for hunting where you can see the target first don't shoot it. If for no other reason than there's diminishing gains from dressing smaller and smaller fish or game. Not to mention the law.
Protectiveness towards juveniles ... eh, fish aren't "cute". But we certainly think goslings, kits and fawns are, not that we hunt any of these when mature (deer taste awful, my mother put her foot down a very long time ago and my father switched to much more tasty elk and moose).
Paper mentions fisher preference for larger prey ("ornamental"); I think another factor, not mentioned, may be our innate protectiveness towards juveniles (children, babies).
Implied but not mentioned is that the evolutionary pressure of predation on juveniles should act more quickly than on adults (because more time needs to have passed to reach adulthood; slower iteration).