We need core to hunt why not fish?
Why? Because although ostensibly the purpose of CORE is to teach ethics AND ensure safety of hunters and others in the woods, the primary purpose is safety, i.e. reducing hunting fatalities. Since it's pretty unlikely that a fisherman can accidentally kill someone in the bush, it's not considered mandatory.
If hunting didn't involve people in the woods with deadly weapons, the 'ethics education' wouln't be sufficient impetus to justify a mandatory course. Not saying it's right, just saying how I think it is.
D$