All Over Japan

Japan’s Blue Glowing Sea: Fantastic Natural Phenomena Known Between Locals

Do you think you want to visit local places for travel?

Actually, I do and recommend you.

It’s because you can encounter unimaginable and unknown sights.

Let me introduce 2 local places Japan.

I’m sure that there are awsome place in the world.

However, Japan has amazing places too.

Luminous Insect at Seaside /Kanagawa Prefecture etc

Best Time to See

Luminous insects are marine plankton.

Their size is about 1 to 2mm in diameter.

We can see them a lot on the beach in the summer.

So the beach emits mysterious blue light at night.

Every year, it is discussed a lot on SNS.

The sight is so fantastic and literally, it’s “blue glowing sea”.

Mainly, it can be seen at Kamakura in Kanagawa Prefecture, Mikawa Bay in Aichi Prefecture, Noto Peninsula in Ishikawa Prefecture, Shimane Prefecture and Tottori Prefecture.

April to August is the season.

Note:Seasons for luminous insects are depend on places.

Mechanism of Luminous Insect

As I said earlier, lluminous insects are marine plankton.

But they don’t emit when they drift sea.

They emit by chemical reaction when they receive physical stimulation.

If you throw a stone, it would be like this.

Then, how does the blue light occur?

luminous insects have substance called luciferin in their bodies which is similar to what the fireflies have.

When luciferin bind to oxygen and substance called luciferase, luciferin-luciferase reaction occurs.

The luciferin-luciferase reaction emit blue light.

Condition to See

Here are some points of condition to see luminous insects.

We can see luminous insect at Pacific Ocean side rather than Sea of Japan side.

・In the areas where the wave is calm

・When the temperature high

・The day after the steaming hot day

The place where the luminous are likely to occur is that the flow of the tide is loose.

Many of luminous luminous appear where the flow of the tide is loose.

Since many of marine plankton are concentrating in one place, it smells little bit bad.

Firefly Squid’s Body Throw / Toyama Prefecture

Best Time to See

It’s not only luminous insects that make “blue glowing sea”.

Firefly squids also create fantastic sights.

Speaking of firefly squid, it’s popular for Japanese to eat as sashimi or boiled with Japanese Vinegar miso.

Especially in Toyama Bay in Toyama Prefecture, many firefly squids come to the shore every year.

Late February to late May at midnight is the season.

Mechanism of Firefly Squids

It is the feature that firefly squids start to emit light when they touch something.

And it is said that they emit light to protect enemies.

Many firefly squids inhabit in Toyama Bay.

So many of female firefly squids lay eggs from the evening to the middle of the night.

After done with spawning, firefly squids are launched to the shore by the waves.

Firefly squids also have luciferin on their bodies.

This is why we can see the blue line at seaside.

Condition to See

It is said between locals that we can see in following situation.

・The day before and after the new moon (invisible night of the moon)

・A day when the tide is high from midnight to dawn

・When the sunny and the sea is a beautiful day

・The day when the wind from the south is blowing

・A day when the waves are calm

Especially, the night of “new moon” is considered high probability to see.

Note: we can’t see it 100%.


Blue glowing sea is so fantastic that you would be moved.

If you have chance, please come to see Blue glowing sea.


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