A surprisingly little-known collection of trivia quizzes and fun facts about the sea
The ocean covers most of the Earth and is very important to our lives.
Many different creatures live in the sea, and fish and seaweed are also part of our diet.
Furthermore, the ocean has a major impact on the climate.
In the ocean, there are places where freshwater and seawater mix.
For living things, the sea is a special habitat.
Here, we introduce general trivia quizzes and fun fact questions related to the ocean.
In the deep parts of the sea, there are still many undiscovered creatures and secrets! Learning more about the ocean helps us feel the importance and vastness of nature.
Please take an interest and explore the world of the sea through these quizzes!
Surprisingly Little-Known Sea Trivia Quiz & Fun Facts Collection (1–10)
What is the deepest ocean on Earth?
- Indian Ocean
- Atlantic Ocean
- the Pacific Ocean
See the answer
the Pacific Ocean
The deepest ocean on Earth is the Pacific Ocean. The Pacific contains the Mariana Trench, one of the deepest places in the world, which reaches a depth of about 10,924 meters.
There was once a fish whose consumption was strictly prohibited. What was it?
- tuna
- pufferfish
- mackerel
See the answer
pufferfish
Fugu contains a powerful toxin, and because accidentally eating it can be life-threatening, ordinary people were forbidden to consume it during the Edo period. However, with changes in food culture and advances in preparation methods, it can now be eaten safely.
In biological classification, the king crab is not actually a crab. So, what group does it belong to?
- Hermit crab and its relatives
- Shrimp and their relatives
- Mantis shrimp and their relatives
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Hermit crab and its relatives
The red king crab may look just like a true crab, but it is actually classified as a relative of the hermit crab. This is because its number of legs and body structure differ from those of true crabs. In Japan it is called a “crab,” but in fact it belongs to a different group.
What are the black dots on the fringe (mantle) part of a scallop?
- digestive gland
- eye
- gill
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eye
The black dots on the scallop’s fringe are its “eyes.” Scallops have many eyes lined up, allowing them to sense things like brightness.
There are three things that squids have in their bodies, of which we humans have only one. What are they?
- eye
- heart
- foot
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heart
Squids astonishingly have three hearts. One is the main heart that pumps blood throughout the body, and the other two are responsible for sending blood to the gills.
There are said to be about 500 species of sharks, but approximately how many of them are known to attack humans?
- about three types
- about 10 types
- about 50 types
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about 10 types
There are about 500 species of sharks in the world, but only around 10 are known to attack humans. Most sharks do not harm people.
Sweet shrimp (amaebi) have an unusual characteristic. What exactly is it?
- The shell is transparent, and the internal organs are visible through it.
- Stay male for life
- Its sex changes as it grows
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Its sex changes as it grows
Amaebi are formally called the northern red shrimp (Hokkoku-akaebi). They are all male at birth and change sex to female as they grow. Many marine creatures share this characteristic, and amaebi are one of them.
What part of the human body corresponds to the hole on top of a dolphin’s head?
- nose
- ear
- mouth
See the answer
nose
The hole on top of a dolphin’s head is called a blowhole, and it’s the organ they use to breathe. It’s equivalent to a human nose, connected to the lungs, and when they surface, they breathe through it.
Which sea has the highest salinity?
- the Baltic Sea
- Red Sea
- the Dead Sea
See the answer
the Dead Sea
The Dead Sea is located between Jordan and Israel and is famous for its exceptionally high salinity—over about 30%—one of the highest among the world’s seas and lakes. Incidentally, despite having “sea” in its name, it is actually a lake.
What does the term “shiome” (the boundary of ocean currents) mean?
- a place where the depth of the sea changes suddenly
- A place where seawater from different currents collides
- where the tide comes in
See the answer
A place where seawater from different currents collides
A tidal rip (shiome) is the boundary line formed where ocean currents with different temperatures or salinity levels collide. It is known as a place where fish tend to gather.