I'm planning a canoe trip with my son. The biggest difference is that unless you will be portaging extensively, weight is not a problem. The canoe rather than your body will carry the burden, so you can be generous in your menu. Apples last well, but pack them carefully as they tend to bruise. If you take bread, choose something with backbone, like sourdough or a hearty all-grain round loaf.
Bagels hold up well, too.
Fluffy bread will get squashed. To protect crackers, carry them in a semi-rigid plastic container. If you use a container that's big enough for the entire lunch and pack it at the top of a pack, you won't have to root around at lunchtime. If you are on a trip that has no portaging, a cooler is an option. On a recent canoe trip, we had steak and potatoes the first night out, and fresh eggs, bacon, and English muffins the following morning.