Quick answer: Give five fish to the hazmat scientist, use the Fish Bucket for the Bowhead Whale, throw its carcass into the crater and defeat the Mutated Bowhead Whale.
Story location order
What makes this island different
Volcano Island contains an optional Goblin Shark and a separate three-step ending chain: collect five native fish for the scientist, defeat the Bowhead Whale, then sacrifice its carcass to start the mutated final boss.
Priority route
- Buy Scientific Lures and give five Volcano-native catches to the hazmat scientist.
- Receive the Fish Bucket, then purchase and upgrade the Assault Rifle before using it.
- Defeat Bowhead Whale by abandoning the landing zone whenever it jumps.
- Carry the whole carcass up the wooden planks and throw it into the crater.
- Defeat the mutated whale, preserve its fin and exchange it for the military-boat key.
Volcano Island route
- Catch five fish for the hazmat scientist.
- Receive the Fish Bucket and prepare an upgraded ranged weapon.
- Defeat the Bowhead Whale and keep the whole carcass.
- Carry it to the crater and throw it into the lava.
- Defeat the Mutated Bowhead Whale and return its fin.
Money and upgrade decisions
Volcano has the highest lure and weapon costs. Ordinary Scientific Lure fishing funds the Assault Rifle, ammunition and healing while also satisfying the scientist’s native-fish request. The Scientific Boss Lure and Goblin Shark are optional, so they should not consume the budget needed for the ending.
Navigation and quest-item route
Identify three landmarks before triggering the whale: the scientist for hand-ins, the open combat ground for safe body-slam exits and the wooden route to the crater. The final carcass goes into the volcano; it does not return to the scientist like earlier trophies.
Main encounter: Bowhead → Mutated Bowhead Whale
Give five fish to the hazmat scientist, use the Fish Bucket for the Bowhead Whale, throw its carcass into the crater and defeat the Mutated Bowhead Whale.
Open the Bowhead → Mutated Bowhead Whale encounter guide →
Progression checkpoints
| Moment | What to confirm |
|---|---|
| Scientist request | Five native fish accepted and Fish Bucket awarded |
| Before Bowhead | Upgraded Assault Rifle, ammunition, healing and open retreat lane |
| Between bosses | Whole whale carcass carried to and thrown into the crater |
| Ending unlock | Mutated fin accepted and military-boat key received |
When to do optional work
Goblin Shark and post-game collection work are best left until the Assault Rifle and whale supplies are secure. The save can continue after the ending, so there is no need to complete every optional catch before using the military boat.
Solo and co-op route differences
Solo
Solo play should use deliberate preparation breaks: finish the five-fish request, upgrade, fight the normal whale, restock, then trigger the mutated form. The second arena becomes less forgiving once lava begins to fall.
Co-op
Keep a common retreat direction during body slams but enough spacing that one lava patch cannot trap everyone. Assign one carrier for the carcass and one caller to watch airborne transitions.
Common route mistakes
- Spending endgame money on Goblin Shark before story preparation.
- Using the Fish Bucket with an unupgraded weapon.
- Standing under either whale during an aerial launch.
- Taking the normal carcass back to the scientist instead of the crater.
Volcano Island FAQ
Do you need to defeat Goblin Shark?
No. It is an optional Scientific Boss Lure encounter and is separate from the whale story chain.
How many fish does the scientist need?
Current walkthroughs specify five fish native to Volcano Island before the Fish Bucket is awarded.
What starts the final boss?
Carry the defeated normal Bowhead Whale up the wooden route and throw the whole carcass into the volcano.
Sources, method and evidence limits
The five native catches, Fish Bucket, optional Goblin Shark, Assault Rifle preparation, crater trigger, lava hazard and military-boat ending are corroborated by current completion, map and boss guides.
- Official How to Fish Steam page — official island-and-boss progression premise.
- Destructoid complete walkthrough — five-island order and quest chain.
- ShowGamer island map — story gates, optional encounters and Radar sequence.
- All Things How vendor guide — item tiers, prices and upgrade availability.