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HOW TO FISH · STEAM PC

Mutated Bowhead Whale: Crater Trigger, Fight and Final Reward

Turn the first Bowhead Whale into the final encounter and bring the correct Fin to the Scientist.

Updated September 7, 2026

Start here

Defeat the first Bowhead Whale, put its whole corpse into the crater and fight the mutated whale. Pick up Whale Fin after the kill, return it to the Scientist and take the black boat home.

Get the first whale onto land

Fill the Scientist’s local five-fish request, collect Fish Bucket and use it on the rod. Bowhead Whale leaps above the camp during combat; keep moving out from beneath it before shooting again.

Reach the crater with the corpse

  1. Pick up the whole dead Bowhead Whale with E.
  2. From camp, follow the wooden planks up the volcano and reach the crater.
  3. Put the body into the lava. The Mutated Bowhead Whale health bar appears after the trigger.
Whole Bowhead Whale above the molten crater
The whole whale is positioned over the crater’s lava. Tap image to enlarge. Image: Common Sense Gamer — Mutated Bowhead Whale

Fight from clear ground

In the recorded fight, the mutated whale closes the distance, rises into the air and slams down among lava patches. Stop firing when its movement closes your escape route, move to clear ground, then resume with the rifle.

CueResponse
Whale approachesMove out of its path.
Whale rises overheadLeave the landing area.
Lava blocks the routeMove onto clear ground before firing.
Mutated Bowhead Whale health bar above glowing whale and lava
Keep the whale and the lava in view when choosing your next movement. Tap image to enlarge. Image: Common Sense Gamer — Mutated Bowhead Whale

Return the Fin and board

  1. Pick up the named Whale Fin [E] after the kill.
  2. Carry it to the Scientist. Collect the keys offered with his return-home dialogue.
  3. At the black boat’s helm, use Get back to the mainland [E]. The scene changes to departure.
Yellow-suited Scientist offering a key with an E prompt
Collect the offered key with E. Japanese version 1.0.9. Tap image to enlarge. Image: Gamerch / わさだ
Named Whale Fin pickup
Whale Fin is a separate pickup after the mutated whale fight. Version 1.0.11. Tap image to enlarge. Image: Checkmark Academy
Black boat return-mainland prompt
Use the boat’s return-mainland prompt after collecting the keys. Version 1.0.11. Tap image to enlarge. Image: Checkmark Academy

Sources and further reading

How to Complete Island 5 in How to Fish (Final Mutated Whale Boss)

KpShamino

How to Fish Game: How To Kill The Bowhead Whale Boss Island 5 Guide

Common Sense Gamer

Gamerch