East Asian finless porpoise

The Korean communities of the porpoise are sometimes known as sanggwaengi (Korean: 상괭이) and the Japanese communities, particularly the subspecies N. p. sunameri, as sunameri (Japanese: 砂滑)(Japanese: スナメリ).

In the Namhae

The species inhabits the coastal areas off mainland China (e.g., Chongming Island)[3] south to the Penghu Islands. The Matsu Islands are thought to be their northern limit, and the local population in this area is physically smaller than the Indo-Pacific finless porpoise. These two species overlap in the Matsu region.[4] The population in coastal waters around Japan is geographically isolated by the deep waters between Japan and continental Asia. Vagrant animals can reach the Ryukyu Islands.

Throughout their range, the porpoises stay in shallow waters, up to 50 m (160 ft) deep, close to the shore, in waters with soft or sandy seabeds, or in estuaries and mangrove swamps. In exceptional cases, they have been encountered as far as 135 km (84 mi) off-shore in the East China and Yellow Seas, albeit still in shallow water.[5]

Finless porpoises can grow to as much as 2.27 m (7 ft 5 in) in length, and can weigh up to 72 kg (159 lb), although most are smaller. Adults grow more than 1.55 m (5 ft) in length and up to 30–45 kg (65–100 lb) in weight.[6] The flippers are moderately large, reaching up to 20% of the total body length. Adults are typically a uniform, light grey colour, although some may have lighter patches of skin around the mouth, or darker patches in front of the flippers. Newborn calves of the central and eastern subspecies are mostly black with grey around the dorsal ridge area, becoming fully grey after four to six months. However, newborn calves of the western subspecies are a light creamy grey, and become darker as they age.[6][7]

In Chinese coastal waters, finless porpoises are generally found in groups of three to six,[12] although aggregations of up to about fifty have been reported.[13] In Japanese waters, groups appear to be smaller, with pairs being typical, and even rare aggregations being no larger than thirteen individuals.[13]

They are reported to eat fish, shrimp and squid in the Yellow Sea/Bohai area. In Japanese waters, they are known to eat fish, shrimp, squid, cuttlefish and octopuses.

The primary danger to the species is environmental degradation. Except for being briefly hunted after World War II due to the lack of seaworthy fishing boats, finless porpoises have never been widely hunted in Japan. It is a species protected since 1930 at the area around Awajima Island, Takehara and this coverage had since been extended to all Japanese coastal waters. A decline of over 50% over the last three generations has been noted in the species, and it is thus classified as Endangered. This decline is largely thought to be a consequence of intensified fishing activity, which has caused large amounts of porpoises to be entangled in gillnets. Habitat loss and pollution are also thought to be major threats.[14]

Local conservation groups in Korea, such as at Yeosu, have started campaigning for the protection of the local populations.[15]

Finless porpoises have commonly been kept in Japan, as well as China and Indonesia. Ninety four in total have been in captivity in Japan, eleven in China, and at least two in Indonesia. Japan has had three establishments designated for breeding them, and there have been five recorded births. Three, however, died moments after birth, but two survived for several years.

• List of cetaceans