fish takes like 5 min to get a stack if you target an area where you see a lot of them swimming. The tuna at 4 a pop fill your bag in a hurry, and the new 5x cooker has them done in no time with less hassle. Are tuna hard to find early game, though? I dunno if they spawn off harder zones or just deeper waters? I have a coast full of them near my home.

Deer are no harder but no easier: you rarely find 10 deer in one place, unlike fish, you have to go looking, and they eat arrows ... if you gonna complain about bait (very cheap item), you have to mention the arrows (even wood ones require farming wood and crafting time, and IMHO more annoying than bait).

I don't like the -5 min issue, that is the deal breaker if choosing which to make. Seems like something to report as a balance issue/bug.

The harpoon is endless utility, from dragging animals around to killing birds without arrows. Make one whether you use it on serpent or not.