Ways/Places to fish on the Island

Once the trap is actually full, which option do you choose to collect the fish/treasures? I know it's not "Release the fish" but I've tried all of the others, and nothing ever shows up in my inventory. (I.e., I select "Check the Trap" and get a notification that it's full, and then there are about four options when I click the trap, but I've tried all of them, and so far, none has worked for me.) I've looked on Carl's Guide, and elsewhere, and no one seems to actually show/discuss which option you are supposed to choose.

I also still don't understand what's up with fishing on the canoe. I've tried sitting on it and lounging on it, and when it even shows up, the fish option is always greyed out, supposedly because the boat is moving, even though it's not.