Ōmura Bay
is a bay located in the center of Nagasaki Prefecture, Japan in the East China Sea. Geography 

The bay measures about  north-to-south and  east-to-west. The length of the shoreline is about  and the surface area is about . 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  and maximum  depth. The bay is surrounded by land in all directions, thus it appears as an inland sea on maps. The only two connections to the East China Sea are in the north-west: the  with a minimum width of  and – more eastward – the  with a width of . However, these two straits do not directly lead to the open sea, but to the . In between the Hario and Haiki Straits lies Hario Island. 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 Ōmura city lies the largest island of the bay: Mishima (箕島), where Nagasaki Airport is located. For this purpose, the island first had to be flattened and reshaped. Along the bay shore lie the following towns, clockwise from the north: Sasebo, Kawatana, Higashisonogi, Ōmura, Isahaya, Nagayo, Togitsu, Nagasaki and Saikai. 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, which does not leave the bay during its lifetime. Indo-Pacific bottlenose dolphins and common dolphins may migrate into the basin on unclear regularities. Another special inhabitant – sometimes characterised as a living fossil – is the horseshoe crab species Tachypleus tridentatus. 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. References 

Bays of Kyushu
Landforms of Nagasaki Prefecture