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Coral species
1. what is coral?
Corals are widely found throughout the world and can be seen in many beautiful forms in the seas around Japan.
Although corals are generally considered to be plants, few people know that corals are actually animals from a biological standpoint.
In this section, we will first discuss basic knowledge of corals.
Corals first appeared on Earth about 400 million years ago, long before the birth of humans.
It looks like a plant, but as mentioned above, it is classified as an animal.
Many corals are cnidarians, the same as jellyfish and anemones, because they have poisonous stingers in their tentacles.
In addition, they are cavity gut animals, which means that they eat and defecate in the same mouth.
If you look closely at coral, you will see that it is formed by a collection of tiny grains, one by one.
These are called "polyps." Roughly speaking, corals are made up of "polyps.
A single coral is made up of nearly tens of thousands of polyps, and as each polyp repeatedly divides, the coral itself grows at a rate of 1 cm to 10 cm per year.
The system also uses polyps to catch and eat zooplankton during the meal.
There are about 200 species of corals in Okinawa alone, which can be broadly divided into "reef-building corals" and "non-reef-building corals.
0 reef-building coral
Corals involved in the formation of coral reefs are collectively called reef-building corals.
Reef-building corals are characterized by the fact that they build calcareous stones under their own skeletons to protect themselves from external enemies, and then live around these hard skeletons.
The calcareous material grows as the coral grows, developing over time into a variety of shapes, including table, branch, and cabbage shapes, which form coral reefs.
0 non-reef-building coral
This is a general term for corals that do not grow in groups but live alone.
The skeleton is polished and sold as jewelry.
There are red corals, peach corals, white corals, and saffron corals, which grow slowly over time in deep waters several hundred meters deep.
It is no exaggeration to say that 1/4 of the fish in Okinawa live on coral reefs.
Some fish make coral reefs their home, while others feed on the reefs themselves.
Coral also has an enormous impact on the ecosystem, acting as a natural breakwater on typhoon and high wave days to protect the organisms that gather there.
0Coral properties
Corals are animals, but they absorb carbon dioxide from the water and exhale oxygen.
This is due to the action of algae called zooxanthellae in the coral.
As a work per unit area of zooxanthellae, it is more powerful than terrestrial plants.
Corals depend on the sugar energy obtained through this mechanism for their livelihood.
Brown algae prefer warm, shallow waters because they live in water temperatures of 18-28°C.
However, non-reef corals that live in deep water do not live in symbiosis with brown algae, allowing them to live in deeper waters with cooler water temperatures.
Corals have a natural enemy, the starfish.
Starfish live in coral reefs and feed on coral, so much so that coral is sometimes killed.
Except for death by external enemies such as starfish, corals have a life span that varies from a few years to several thousand years, depending on the type of coral.
In addition, corals release their eggs once a year, mostly all at once on the night of the full moon.
0 Coral bleaching
Coral bleaching occurs when colorful coral turns pure white and eventually dies.
In Okinawa, there was a massive bleaching in 2016.
The zooxanthellae that live symbiotically with corals will decrease in number if they continue to be stressed due to climate change or water pollution, and as a result, the corals themselves will turn white.
At first, the coral can continue to live, but after about two weeks of this condition, it will die.
However, recent research has shown that zooxanthellae that are facing death are photosynthesizing at two to three times the capacity of normal zooxanthellae.
So the zooxanthellae are not just dying, but are also trying to keep the coral alive until the end.
2. coral of Miyako Island
It is said that there are 600 to 800 species of corals in the world's oceans, and more than half of them live in the seas of Okinawa.
In addition, new species continue to be discovered one after another in Okinawa.
Therefore, it is no exaggeration to say that it is the best coral sea in the world.
The coral reefs of the Okinawa Sea are said to be located in the northern part of the world's distribution range.
Coral reefs grow only in warm seas like those in Southeast Asia, but in Okinawa, the warm Kuroshio Current and the clear, deep waters that allow sunlight to penetrate deep into the coral reefs allow coral growth.
Coral reefs form around the islands and protect the land as a breakwater around the islands, providing a place for many creatures to live and protect their ecosystems.
3. coral species
008 coral (Corallium japonicum)
It is so-called gemstone coral.
They form dendritic aggregations in the deep sea, but because they grow very slowly, damage and declining numbers of organisms due to smuggling and overfishing have become a problem.
Four species of corals, red coral, white coral, peach coral, and mid coral, are listed in CITES Appendix III.
spheniscid coral
Most reef-building corals are included in this category.
Polyp structure similar to sea anemones, developing a calcareous skeleton between septa.
The body, similar to a sea anemone, is soft and has tentacles with poisonous needles, most of which are not harmful enough to humans, but some, such as the anacardia, have powerful venom.
◉Common coral
These beautiful corals live in quiet reef pools on coral reefs.
It grows in a thin, broad, leaf-like shape and clumps together in layers to form large clumps.
◉ Sawtooth coral (Corallium japonicum)
A "wedge" is a mushroom.
The basic shape of the kusabiraishi is a mushroom-like form.
The body is disk-shaped or oval, with a larger groove in the middle as the mouth and tentacles stored between the radial grooves.
Eurasian gregory (Stegastes fasciolatus)
It is one of the most common species of short-branched corals.
They can be found at depths of 10 m or shallower.
The color depends on the symbiotic zooxanthellae and can vary from green to pink to purple.
Small crustaceans are the preferred home.
Characterized by their susceptibility to high water temperatures, they inhabit relatively deep water.
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This cauliflower-shaped coral, 15-20 cm in diameter, is often found on floats and piles.
They are often found on coral reefs several meters deep.
Coral crabs, coral tephra shrimp, and dalmatid gastropods live among the branches.
Rhododendron metternichii var.
A type of reef-building coral with massive or hemispherical colonies.
Polyps are round, 5-6 mm in diameter, small (less than 30 cm), and brown in color.
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These corals form branching colonies.
Various species of sparrowhawks live in the crevices.
In the spring, kobushi come to lay their eggs.
This species is not favored by starfish and is frequently seen because it is resistant to bleaching.
Hydrofluorine coral
Also called coral gudgeon or anacardium coral gudgeon.
Some grow as large as corals and anemones and are considered reef-building corals.
0 soft coral
Called soft corals, they form soft clusters of fine skeletons in discrete pieces.
The term is used to refer to goat, crested, isobana, and other soft-bodied corals that are different from reef-building corals.
It is colorful and looks like a plant.
How to enjoy corals in Miyako Island?
So, how can we enjoy coral viewing in Miyako Island?
In fact, Miyakojima itself is an island formed by coral uplift.
When one thinks of Miyako Island, white sand beaches come to mind.
That beautiful white sandy beach was formed by broken coral scattered all over the place.
Here are some of the spots on Miyako Island where you can see such beautiful coral sights.
<Yaebiji (Yaebiji)
Yaebise is one of the largest coral reefs in Japan, measuring approximately 17 km from north to south and 6.5 km to the northeast, and is designated as a national natural monument.
At low tide, coral reefs rising out of the sea can be seen.
If you want to see coral reefs on an impressive scale, Yaebise is just the perfect spot.
<Yoshino Coast
Approximately 30 minutes by car from Miyako Airport.
Snorkeling can be enjoyed at Yoshino Beach on the east side of Miyako Island.
Because coral colonies grow only a few meters from the beach, this area is popular among tourists as a spot where they can easily enjoy viewing coral.
The variety of food stalls and rental stores make it an easy place to visit.
Since the coral dries up at low tide, snorkeling is recommended at high tide.
Also, when snorkeling, be careful not to step on coral and injure yourself.
The sight of colorful fish swimming among the coral reefs is truly spectacular.
If you are lucky, you may even see sea turtles swimming.
5. summary
There are a wide variety of corals, each with different colors, patterns, and sizes.
Corals distributed in deep waters, such as "octocorals" (gemstone corals), cannot be seen by diving, but other corals can be seen by snorkeling and other sea activities.
The so-called "iscorals" are found on coral reefs.
Why not take a look at the fascinating world of diverse corals that can be seen only on Miyako Island?
This article was written by.
