@Digizel I love where your head is with this.
1. Yes, Saur can Hunt Prey (he's a hunter after all!). That will give Saur a +2 to his Survival check.
2. For Saur's Foraging feat, sure you're not Subsisting, but story-wise there is not a difference in my mind between Saur fishing for himself/the group and Saur fishing to fulfill a task. You can use Forager for this. (This will be in effect off his Stealth roll below)
"While using Survival to Subsist, if you roll any result worse than a success, you get a success. On a success, you can provide subsistence living for yourself and four additional creatures, and on a critical success, you can take care of twice as many additional creatures. You can choose to support half the number of creatures with a comfortable living."
2. Is Saur Trained or an Expert in Survival? Forager lists a larger haul for Expert.
3. Roll Survival to find the fish that are particularly valuable to Alandri. (You get a +2 circumstance bonus to this roll for Hunt Prey), a success can give you a +1 (success) or +2 (crit) bonus to your Stealth check to capture the fish.
4. Roll Stealth to see if Saur can stand perfectly still to let the fish swim toward him, in the perfect location. (Success will catch 1 fish normally, 2 for a Forager. Crit would catch 2 fish, 4 for a Forager.) <- If Saur is an expert, double the Forager success amount.
UPDATE:
Here's the DC for your Survival roll so you can write a post around it's success (for your Stealth).
DC: 8