With Reel Technique and Angler's Instincts active and Arteum pickled fish bowl eaten, I've managed to get my boat. There are still problems with some fish being particularly hard to catch, while other zones were ticked off quickly. Fishing with at least 1 other person frequently lead to double catches and at least 1 occasion of 2 of the blue achievement fish on the same hook.
The final and most frustrating one was the ocean fishing in Cyrodiil. This took more than one session and I had more than 40 of the green fish, plus a mind numbing amount of other fish to auto-fillet, in my bags when I finally caught the blue quality fish. I can't unfortunately say how many it really would have been, as I'd already cleared out my bags part way through.
Plenty of furnishings along the way, as well as some decent stuff out of the gunny sacks.