I was looking to expand my crew of fishermen by two. Here's my question, will the anti-macro gump show up if I lock fishing at 99.9 while in the deep sea fishing off a boat? Thanks!
You will not get the gump at 99.9 fishing. Locking at that is a not uncommon thing with some fishers. You'll miss out on fishing up MIBs and AMIBs on those toons though (100 skill required).
No, you will pull up serpents or deep sea serpents at 80+, which will kill you. It's best to stay ashore until you get to 99.9 skill. Takes a few days but it's worth it if you're just macroing but beware, once you hit 100%, you will get the unattended macro gump.
You can even get around that by only setting other skills 'down' with just enough to hit 99.9 (i.e. fishing + all skills set down = 99.9). You can fine tune it by buying just the right amount of skill points from NPCs. You can also buy 1 gold (0.1 skill points) from an NPC with fishing set to down to convert your GM to 99.9 if you decide to.