Congratulations on Construction, that's a very respectable skill.
I know you're not currently training it, but I was wonder why you're choosing to do Barbarian hand fishing? From what I know it's good xp, but the only difference from regular harpooning is that it gives strength xp along with fishing xp, and you don't really need more strength xp, hah.
As an alternate option, I suggest fly fishing either in Shilo Village or a really nice spot I found. It's west of the Fishing Guild along a river. Catch your fish, run a bit north and sell them to a traveling salesman, then repeat. You don't get to keep your fish which is a downside, but the xp is the fastest I've ever collected.
Anyways, good luck with summoning and slayer!
With much support,
Ktoe
Relatively fast Fishing XP not to mention Agility to boot. Decorated Fishing Urn should add at least 10k to 15k.
Thanks for sharing your training tip, Ktoe.