A mutation is a special fishing outcome that replaces the normal catch with something else:

• special fish
• nets
• maps
• SOS bottles
• pirate maps
• sea creatures
• debris/junk

Mutations are governed by:

• Fishing skill thresholds
• Deep water requirements for certain entries
• Optional hook behavior (some hooks reduce junk outcomes)

Examples of mutation results players will encounter:

• Special Fishing Nets
• Treasure Maps
• Message in a Bottle (SOS)
• Pirate Treasure Maps
• Ship debris and salvage items
• Big fish / sharks / jellyfish tier catches
• Junk pulls (boots/shoes etc.)

Some mutations explicitly require deep water. If you are too close to shore (not deep water), those entries cannot trigger.

You will notice a strong “late-game” curve:

• Higher skill opens higher-tier outcomes
• Rare group fish are gated at 110.0+
• Map/treasure systems generally become reliable in higher bands

Exact weights and per-entry probabilities are configured in the mutation tables inside the fishing engine. If you want the wiki to display raw percent tables, add a “Developer Appendix” section and maintain it alongside code changes.