A rich ecosystem
A precious and rich ecosytem not only gives Amakusa its island charm,
but unique sea bottom topography also provides a home to a pod of
dolphines that can be seen year round.
The Year-round dolphins of Amakusa
Dolphin watching has become a special point for sightseeing in Amakusa. Though the breed of dolphin found in Amakusa typically migrate the oceans world-wide, the dolphins of Amakusa take up residence throughout the year due to the undulating nature of the sea bottom and its ability to supply just the right living environment for many sea creatures that sustain the dolphin's existence.
（１）Indo-Pacific bottlenose dolphin
There is a high probability of observing Indo-Pacific bottlenose dolphin of which about 200 live in the Hayasaki strait between Amakusa-shimoshima and the Shimabara peninsula. Dolphin watching adventures allow participants to catch a glimpse of the strait and its ecosystem.
（２）Hakusen-shiomaneki crab colony in the Nagaura island
The tidal flats on the circumference of Nagaura island are known as a leading habitat of the fiddler crab in Japan, which bears the Japanese name ‘hakusen shiomaneki’. This crab is about 2 cm in length, and the male sports a single large, white scissor-claw on one of its front appendages.
（３）The Marsh of Shiratake Mountain
The Shiratake marshes with an altitude of 280m are formed between Shiratake and Nokogiridake. On the circumference of the marshes, we can observe about 50 varieties of dragonfly such as the smallest Japanese speceis known as Hachyotombo, and the biggest known as Oniyanma, as well as rare subtropical plants such as Himozuru.
（４）Calcareous algae on the coast
You can see many balls of calcareous algae (Lithophyllum sp.) at about 4cm in diameter strewn on the beachs on the circumference of Tsujijima. Rare calcareous balls colored light purple red may also be found.
（５）Tomioka marine park
The southwest part of the Tomioka peninsula is specified as a marine park, with a beautiful coral reef, black rocks (alternation strata of black shale and sandstone of the Sakasegawa Group) and white rocks (rhyolite: volcanic rock) which expand at the shoreline and the cliff jutting out into the sea from the peninsula.
（６）Ushibuka marine park
Visitors to the area enjoy the sight of many colourful fish swimming and the bountiful coral from the vantage point of glass-bottom boats. The Shishiboe-misaki looks like the shape of the head of a lion and consists of eroded volcanic sediments (tuff breccia) which build along the seashore.