Professions in multiplayer Stardew Valley have two variations:
- Professions that affect item selling price apply to all players, as long as the player with that skill is online.
- Professions that affect gameplay in other ways apply only to that player.
Before 1.5.3: When a player places a crab pot with either the Mariner or the Luremaster profession, the effect is tied to that crab pot. That means that the bonus will remain so long as the pot remains there, even if another player collects from it. However, if another player without the profession breaks the crab pot and replaces it, it will no longer have the effect from the profession.
Since 1.5.3: When a player refills a crab pot, their professions get applied to that pot.