The Marine Research Event in Become a Deep Sea Explorer runs as a ten-quest chain that mixes fishing, treasure hunting, and a timed deep dive, then finishes with a scavenger hunt for boat parts. Finishing everything hands you the Eternal-tier Warzoid Marlin.
Quick answer: Complete all 10 event quests, collect the 11 hidden boat parts scattered across the Coral Reef, Kelp Forest, Shipwreck Graveyard, and Bioluminescent Abyss biomes to assemble the event vehicle, then talk to Mariner Tobe at the Research Center to claim the Warzoid Marlin.
All 10 Marine Research Event quests
The quests unlock in order and cover several fish rarities, treasure grades, and one endurance objective. Note the exact conditions on Quest 8 (daytime) and Quest 9 (no missed green bar), since those are the ones players most often fail.
| Quest | Objective |
|---|---|
| 1 | Catch 20 fish (start in the Coral Reef, e.g. Clownfish, Damselfish, Anthias) |
| 2 | Collect 10 treasures such as Pearls, Coin Pouches, Coins, and Rings across Coral Reef and Kelp Forest |
| 3 | Collect 5 Super Rare fish (Black Arowana, Black Marlin, Dark Barracuda, and similar) |
| 4 | Dive below 20m for 20 minutes in the Kelp Forest |
| 5 | Catch 7 “Specimen” fish (Specimen Eel, Specimen Treefish, Specimen Trout) |
| 6 | Collect 6 Rare or higher treasures (Chests, Crowns, Diamond Necklaces) |
| 7 | Catch 3 “Tracked” fish (Tracked Napoleon, Tracked Sea Dragon, Tracked Dolphin, Tracked Tigerfish) |
| 8 | Catch 10 Mythical fish in the daytime (Atlantic Trumpetfish, Deep Sea Angler Fish, Clown Parrotfish) |
| 9 | Catch 10 Rare or higher fish without missing the green bar (Bluefin Tuna, Wrasse, Lion Fish) |
| 10 | Catch 15 “Marine Research” fish (Mutagen Butterflyfish, Mutagen Marlin, Mecha Manta, Mecha Thunnus, Mecha Dunkleus, Mechalodon) |
Special event fish categories
Three quests point to fish that only appear for the event, so ordinary catches will not count toward them.
- Specimen fish — needed for Quest 5. Examples include Specimen Eel, Specimen Treefish, and Specimen Trout.
- Tracked fish — needed for Quest 7. Examples include Tracked Napoleon, Tracked Sea Dragon, Tracked Dolphin, and Tracked Tigerfish.
- Marine Research fish — needed for Quest 10. This is the toughest set, covering Mutagen Butterflyfish, Mutagen Marlin, Mecha Manta, Mecha Thunnus, Mecha Dunkleus, and Mechalodon.
Tip: Quest 4 is passive as long as you stay under 20 meters, so pair the 20-minute dive with treasure hunts or fishing to bank progress on other quests at the same time.
Hidden boat parts and where to search
Alongside the quests, you need to find every boat part to build the event vehicle. The parts are hidden across the four biomes rather than in one place, so plan a sweep through each area. When you touch a part, a “Collected Successfully” message confirms the pickup.
| Boat part | Pickup confirmation |
|---|---|
| Antenna | Antenna Collected Successfully |
| Boat Wing (Left) | BoatWingLeft Collected Successfully |
| Boat Wing (Right) | BoatWingRight Collected Successfully |
| Command Deck | CommandDeck Collected Successfully |
| Crane Arm | CraneArm Collected Successfully |
| Helipad | Helipad Collected Successfully |
| LED Rig | LEDRig Collected Successfully |
| Spoiler | Spoiler Collected Successfully |
| Steering Pad | SteeringPad Collected Successfully |
| Turbine Jet | TurbineJet Collected Successfully |
| Twin Hull Body | TwinHullBody Collected Successfully |
The parts sit in the Coral Reef, Kelp Forest, Shipwreck Graveyard, and Bioluminescent Abyss. The Abyss is the deepest zone, so upgrade your breath before heading down to grab anything located there.
Claim the Warzoid Marlin from Mariner Tobe
Why a quest may not complete
- Quest 8 only counts Mythical fish caught during the day. Catches made at night will not register.
- Quest 9 resets your streak if you miss the green bar during the catch minigame, so a clean catch is required for all 10 fish.
- Quests 5, 7, and 10 only accept the event-specific Specimen, Tracked, and Marine Research fish, not standard species of the same name.
- Quest 4 pauses if you rise above 20 meters, so the 20-minute timer only advances while you stay below that depth.
Work through the quests in order, keep the depth and daytime conditions in mind, and sweep each biome for the boat parts as you go. When the Warzoid Marlin lands in your collection, the Marine Research Event is done.
