Direct answer
Defeat Tuna with a controlled late-game loadout, then do not sell or lose the body: route reports use it as the Albatross bait step.

Recommended preparation
The goal is not a mathematically perfect build; it is a loadout that lets you move, recover and finish the hand-in without restarting the island.
- Professional boss lure
- Sustained ranged damage
- Empty boat storage
- A clearly assigned item carrier
Fight plan
- Prepare the lure and arena.
- Finish the encounter.
- Move the Tuna to protected storage.
- Take it into the Albatross chain instead of the sale pile.
Route status: Patch-sensitive. Avoid selling a named body part, trophy or bait object until the local quest giver rejects it.
Difficulty and co-op adjustment
Patch 1.0.9 added Easy and Hard. Easy reduces creature health by 25% and damage by 50%; Hard increases health and damage by 25%. In co-op, spread out, assign one item carrier, and call reload windows instead of emptying every weapon at once.
Compare all difficulty settings →