is a bay of the East China Sea

East China Sea

The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...

 in the centre of the Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese Nagasaki Prefecture

Nagasaki Prefecture

is a prefecture of Japan located on the island of Kyūshū. The capital is the city of Nagasaki.- History :Nagasaki Prefecture was created by merging of the western half of the former province of Hizen with the island provinces of Tsushima and Iki...

.

Geography

The bay measures about 26 km (16.2 mi) north-to-south and 11 km (6.8 mi) east-to-west. The length of the shoreline is about 360 km (223.7 mi) and the surface area is about 320 square kilometre. This corresponds with about 8% of the total area of the prefecture. Compared to its size, the bay is relatively shallow with an average depth of 14.8 m (48.6 ft) and maximum 54 m (177.2 ft) depth.

As a special feature, the bay is surrounded by land in all directions. So, from its form the bay appears as an inland sea. The only two connections to the East China Sea are in the north-west: the with a minimum width of 200 m (656.2 ft) and – more eastward – the with a width of 10 to 200 m (32.8 to 656.2 ft). However, these two straits do not directrly lead to the open sea, but to the . In between the Hario and Haiki Straits lies . West of the Ōmura Bay lies the , and to the south is the foot of . On the eastern shore of the bay is the , on which the city of Ōmura is located.

Opposite to Ōmura city lies the largest island of the bay: Mishima (箕島), which locates Nagasaki Airport

Nagasaki Airport

is an international airport located west of the railway station in the city of Ōmura and north northeast of the Nagasaki railway station in the city of Nagasaki, Nagasaki Prefecture, Japan...

. For this purpose, the island first had to be flattened and reshaped.

Along the bay shore lie the following towns, clockwise: Sasebo

Sasebo, Nagasaki

is a city located in Nagasaki Prefecture, Japan. As of 2011, the city has an estimated population of 259,800 and the density of 609 persons per km². The total area is 426.47 km². The locality is famed for its scenic beauty. The city includes a part of Saikai National Park...

, Kawatana

Kawatana, Nagasaki

is a town located in Higashisonogi District, Nagasaki, Japan.As of January 1, 2009, the town has an estimated population of 14,760 and a density of 396 persons per km². The total area is 37.25 km²....

, Higashisonogi

Higashisonogi, Nagasaki

is a town located in Higashisonogi District, Nagasaki, Japan.As of January 1, 2009, the town has an estimated population of 9,219 and a density of 124 persons per km². The total area is 74.25 km². There is one convenience store, four gas stations, a park, a boat pier, a hospital, 5 clinics, 2...

, Ōmura

Omura, Nagasaki

is a city located in Nagasaki Prefecture, Japan. As of January 1, 2009, the city has an estimated population of 89,891. The total area is 126.33 km², and includes Nagasaki Airport.-History:...

, Isahaya

Isahaya, Nagasaki

is a city located in Nagasaki Prefecture, Japan.The city was founded on September 1, 1940. On March 1, 2005, the city expanded through a merger with the surrounding towns of Tarami, Moriyama, Iimori, Takaki and Konagai merged to form the new city of Isahaya...

, Nagayo

Nagayo, Nagasaki

is a town located in Nishisonogi District, Nagasaki, Japan.As of January 1, 2009, the town has an estimated population of 42,215 and a density of 1,470 persons per km². The total area is 28.81 km².-External links:*...

, Togitsu

Togitsu, Nagasaki

is a town located in Nishisonogi District, Nagasaki, Japan.As of January 1, 2009, the town has an estimated population of 30,023 and a density of 1,450 persons per km². The total area is 20.73 km².-External links:*...

, Nagasaki

Nagasaki

is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan. Nagasaki was founded by the Portuguese in the second half of the 16th century on the site of a small fishing village, formerly part of Nishisonogi District...

 and Saikai

Saikai, Nagasaki

is a city located in Nagasaki, Japan.Saikai City was formed through the merger of five towns on the northern tip of Nishisonogi Peninsula on April 1, 2005: the former town of Saikai, Ōseto, Ōshima, Sakito and Seihi, all from Nishisonogi District...

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Biology

Because of the geography of the bay there is only a small exchange of water from the bay with the sea. Consequently, the marine life in the bay is different from that in the nearby sea. The bay houses a rare species of finless porpoise

Finless Porpoise

The finless porpoise is one of six porpoise species. In the waters around Japan, at the northern end of its range, it is known as the sunameri . A freshwater population found in the Yangtze River in China is known locally as the jiangzhu or "river pig". There is a degree of taxonomic uncertainty...

, which do not leave the bay during their lifetime. Another special inhabitant – sometimes characterised as a living fossil

Living fossil

Living fossil is an informal term for any living species which appears similar to a species otherwise only known from fossils and which has no close living relatives, or a group of organisms which have long fossil records...

 – is the horseshoe crab

Horseshoe crab

The Atlantic horseshoe crab, Limulus polyphemus, is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs. Horseshoe crabs are most commonly found in the Gulf of Mexico and along the northern Atlantic coast of North America...

 species Tachypleus tridentatus

Tachypleus tridentatus

Tachypleus tridentatus is a species of horseshoe crab found in China, Indonesia, Japan, Malaysia, the Philippines, Taiwan, and Vietnam....

. Despite being nearly separated from the sea, and the large cities along its shore, the bay is full of fish. About 60 species of marine animals are fished upon.