砂浜・磯・干潟など、自然のままの海岸が残されている九十九島では、
島々の栄養を含んだ水が海へと流れ込み、多くの水生生物を育んでいます。
その中には、日本本土では絶滅寸前のものも少なくありません 。

Horseshoe crab

All year

Horseshoe crabs are rare creatures listed as endangered in the Ministry of the Environment's Red Data Book. It was also called "living fossils" and once lived abundantly on the earth. Many precious horseshoe crabs live on Kujukushima.

Onchidium hongkongense

All year

It is said to be near extinction in mainland Japan, and it is confirmed that it lives in Kujukushima tidal flat.

Sand bubbler crab

April to November

Similar to the Ilyoplax pusilla, but the Ilyoplax pusillar prefers tidal flats, while the sand bubbler crab prefers sandy beaches, so you can judge which one is based on the quality of the soil.
Also, if a small sand dango of about 3mm spreads on the tidal sandy beach, it may be after eating the sand bubbler crab.
Instep width: about 1cm

Shuttles hoppfish

April to November

The shuttles hoppfish is a fish, but does not like to be immersed in water, and is usually on wet rocks or tidal flats. Fish can only breathe in water, while a shuttles hoppfish is breathing with a little water in the mouth. Also, when you escape as the name suggests, you escape while jumping on the water surface.
Body length: about 7cm

Ilyoplax pusilla

May to August

Crabs are often standing still in groups, but they come out of their burrows all at once to eat and waving. These crabs are blue and very noticeable.
Instep width: about 1cm

Uca lactea

May to August

A male uca lactea has a large scissor, which raises the scissors and appeals to the female. This action is called" waving, "because it appears to wave the tide by waving a white fan. Named.
Instep width: about 4cm

Spotted jelly

July to September

This name was given because its shape and color resembled an octopus. The body is brown because algae called zooxanthellae coexist. In rare cases, there are different colors such as blue and gray.