Date & Time: 12:22 PM MST
Frequency: Always
Class/Level: Fisher 98
Party or solo: Solo
In-game time: 6:00pm
Area and coordinates: Yak T'el, 9.8, 12.9
Steps:
1. Begin Mamool quest Fresh Cleaning Supplies
2. Use Patience II at the fishing hole Xd'aa Talat Tsoly
3. Wait until a large (!!) fish bites
4. Attempt to reel fish in with Powerful Hookset. It will fail.
5. Try again. Wait until a large fish bites (!!)
6. Attempt to reel fish in with Precision Hookset. It will succeed.
7. Repeat as many times as needed to remove the possibility of bad RNG

It seems more likely that Ut'ohmu Trout is supposed to have a small (!) bite instead of a large one, given that all of the other quest fish I've seen so far are also small bites. But whichever the intended designation is, the current one is bugged.