You evidently didn't check the level 76-80 fishing delivery ventures. I use my fishing retainer to get the Rose Shrimp and Sweetflesh Oysters for Blood Bouillabaisse. It can also get Megapiranha, though I don't bother with that. I wouldn't be surprised if Sweetmeat Mussels get added to the delivery list in the last half of this expansion just as Usuginu Octopus was added in the last half of Stormblood.
Fishing's been useless for ALC so far this expansion outside of reduction for aethersands, and a retainer can't do that. Hopefully they'll add a fishing ingredient for the 5.2 crafted gear alkahests.
