I've seen several people saying that you can no longer get scales solo using the harpoon. Just tried it myself to see whether this was true - managed to harpoon and land 3 serpents in a row without issue. Didn't even have to lure them further in to shore before harpooning them, because although the harpoon does now drain more stamina when something is pulling against it, it also drains no stamina (and in fact lets you regen stamina) when whatever is on the end is chasing you. I had full stamina when landing 2 out of the 3 serpents and just shot them to death. The 3rd pulled against the line more and I had to use a stamina mead.