The Oceans Surrounding Yakushima Island, Japan
- ThePersaudCatalog
- Mar 20
- 5 min read
Today’s article will discuss the oceans surrounding the island of Yakushima, Japan. Yakushima, Japan is located in the Kagoshima Prefecture. The island is in Southern Japan, & is located in the Ōsumi Islands archipelago.
The island is known for its beautiful cedar wood forests, macaque monkeys, deer, Yaku Sagi trees, & their loggerhead turtle sights. Approximately 40% of all Loggerhead turtles coming into Japan come to Nagata Beach, on northern Yakushima Island. A big reason for the island being able to host such wonderful creatures is because the Yakushima National Park takes up 42% of the island. Part of this national park also includes a marine reserve, which hosts some of the loggerhead turtles.
The name Yakushima translated into English means “Medicine Island”, due to the medicinal properties of the herbs there. Yakushima Island is approximately 285.58 nautical miles (328.639595 miles or 528.89416 kilometers) from mainland South Korea. Yakushima island is approximately 194.9 square miles (504.78868 square kilometers), of which 83.807 square miles (217.059134 square kilometers) is a National Park. Part of this national park contains a marine sanctuary, which protects the various marine creatures.
Additionally, the island has beautiful small lagoons, frequently visited by locals & tourists alike. These small lagoons provide a glimpse into what is considered the “other-worldly” marine ecosystems. The most popular beaches on the island are Isso Beach, Kurio Beach, Nagata Beach, Inakahama Beach, & Jodogahama Beach.
In this article, we will discuss the salinity, tides, temperatures, & marine geography, of the island, the most prominent ecosystems of the island, the documented marine flora & fauna, & Finally, & how ocean acidification has affected the island. With that being said, let us delve into the oceans surrounding the spectacular, Yakushima Island.
The Salinity, Tides, Temperatures, Marine Geography, & Basic Information Of The Oceans Surrounding Yakushima Island
Unfortunately, the salinity of Yakushima Island has yet to be measured. Since Yakushima Island rests in the Northern Pacific Ocean, it has a lesser salinity than the Atlantic. Salt deposits or brine pools have not been proven to be found around the island in higher concentrations than other areas. However, this could change. Since the average salinity of the water in the Pacific Ocean is 35 parts per thousand at any given time, it can be assumed that the salinity level is somewhere around that number. Salinity is measured in 1,000 grams. For every 1000 grams of water, there will be a certain number of grams that are pure salt. This is the way that salinity is currently measured.
There are no external factors currently that seem to be affecting the salinity either. The tidal charts for Yakushima Island can be found on a variety of sources, including https://tides4fishing.com, https://www.seatemperatu.re, & https://www.tideschart.com. The tide usually never gets over 6.7 feet (2.04216 meters). The temperature charts for Yakushima can be found on similar websites, such as https://tides4fishing.com.
As far as we are aware, Yakushima does not have high riptide, & is completely safe for swimmers, with the most popular beach for swimming being Isso Beach. Pollution isn’t an issue either, as the Japanese Government takes sanitation measures very seriously. Scuba diving, kayaking, and snorkeling are also fairly common, as Yakushima does have beautiful coral reefs. Due to the average temperature being a fair 66.56° Fahrenheit (19.2° Celsius), a 5-millimeter full-coverage wet suit is suggested to comfortably swim. Though in the summers, the temperature can go well over 28° Celsius (82.4 Fahrenheit) making it so that no wetsuit is required.
The primary substances composing the oceanic floor are coral, sand, & rock. We unfortunately, are unable to figure out how deep the oceans surrounding Yakushima are, due to poor oceanic floor maps.
The Most Prominent Marine Ecosystems Of Yakushima Island
Ecosystem Type No. 1: Fringing Coral Reefs
The coral reefs nearby are usually within 30 feet of surface level & are directly against the coastline. They are absolutely beautiful & attract millions of dollars in tourism each year. These areas serve as a home, a habitat, & a hunting ground for many creatures. Not to mention that the coral itself is alive. The types of coral reefs around Yakushima, are known are fringing coral reefs instead of barrier reefs. Unfortunately, coral is extremely susceptible to oceanic acidification, as well as negative human activity. It is for this reason that there should be active conservation work to prevent the death of Yakushima’s beautiful coral reefs. Currently, these coral reefs house roughly 1 third of all fish species around Yakushima island, of which there are approximately 520. These coral reefs bring in the strangest of creatures, from sea snakes to pufferfish, Yakushima is an island that never ceases to amaze.
Ecosystem Type No. 2: Rocky Lagoons
The lagoons around Yakushima are usually fairly shallow, & are often visited by humans. These lagoons usually have many different species of waterfowl nearby them, as the waterfowl prefer these kinds of ecosystems. These ecosystems also usually have patches of marine seagrass. These ecosystems are found fairly frequently around the island, & are often swimming in due to their shallow waters, & often beautiful views. This ecosystem is less biodiverse, but it is just as important. Usually, they are extremely close to the coastline, & have underwater rock formations near them.
The Documented Marine Flora Of Yakushima Island
Unfortunately, we are unable to confirm what species of marine flora are found around Yakushima. This is largely due to the marine plant life of Yakushima being understudied.
The Documented Marine Fauna Of Yakushima Island
Yakushima is extremely biodiverse on both land & in the sea. This is due to the extremely desirable conditions of Yakushima. These conditions are there largely due to the Kuroshiro Current, which supplies warm water to the island year-round. This gives Yakushima a much milder winter compared to the rest of Japan. These conditions are evidenced in that Yakushima island has approximately 520 species of Ray-Skinned Fish, & 78 species of marine mollusks. For those who would like to see a list of all of these species, please visit https://www.inaturalist.org. The island has at least 2 species of endemic fauna, but neither of them are aquatic.
By far, the most prominent species of marine fauna on the island is the Loggerhead turtle. It is extremely hard to establish how many species are in Yakushima at any given moment, as the majority of creatures migrate. For example, the Loggerhead turtle only migrates to Yakushima from April to September, to nest. This is why, all research experiments about the amount of marine fauna around the island must be done over a drawn-out period The best place to see Marine life on the island is Isso Beach, located on the northwestern side of the island.
Directories / Credits
Citation No. 1: “Diving & Snorkelling” Written By Unknown & Published at an Unknown Date. Published By Yes Yakushima. Retrieval Date: October 5th, 2023.
Citation No. 2: “Wetsuit thickness and temperature guide” Written By Mark Evans, & Published On April 24th, 2023, at 3:05 PM. Published By Scuba Divers Magazine. Retrieval Date: October 5th, 2023.
Citation No. 3: “Yakushima, JP, KS”, Written By To Many To Name, & Published at Varying Dates. Published By INaturalist. Retrieval Date: October 5th, 2023.
Citation No. 4: “MARINE LIFE in YAKUSHIMA” Written By Yakumonkey, & Published at an Unknown Date. Published By Yakumonkey. Retrieval Date October 5th, 2023.
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