Anadara kagoshimensis
Anadara kagoshimensis is an ark clam in the family Arcidae. It can be found in shallow water in temperate parts of the west Pacific Ocean and is cultivated in China, Japan, and Korea for human consumption. It is known as maohan in China and salubowgai in Japan.
Description
Anadara kagoshimensis has a white or cream coloured, thick, oval shell and superficially resembles a cockle. The left valve is slightly more concave than the right one, and there are 31 to 35 deeply indented ribs. The thin brown periostracum layer that covers the shell flakes off in strands. When harvested for human consumption, the length of Anadara kagoshimensis is usually in the range.Distribution and habitat
Anadara kagoshimensis is found around the coasts of Japan and South Korea, buried in soft sediments in the subtidal zone. It favours mud or muddy sand. Some authorities maintain that the larvae, known as spats, need some hard materials such as stones and shells on which to attach themselves by their byssal threads. Other authorities claim that the larvae do not need hard substrates on which to settle. Anadara kagoshimensis is tolerant of low salinities and favours waters in the range 29–32 ppt. While the larvae are planktonic, they have a preference for even lower salinities of between 24.6 and 30 ppt and tend to congregate in estuarine waters with this degree of salinity. The clam thrives in waters varying in temperature between 5 °C and 28 °C. It also tolerates the low dissolved oxygen levels of tidal waters sweeping in over mud flats. It may be aided in this by the haemoglobin and erythrocytes found in its blood.Biology
Anadara kagoshimensis becomes mature at a length of about. Individual clams are either male or female and spawning takes place between June and September. Fertilisation is external and the larvae form part of the zooplankton, drifting with the currents.Anadara species do not have long siphons but normally lie in the sediment with their posterior end level with the surface or in a slight depression in the mud. The feeding habits of Anadara kagoshimensis have not been researched but are likely to be similar to those of the closely related Anadara granosa. That clam is thought to filter particles out of the water with its gills but also to feed on detritus and microorganisms in the sediment. This ability to live and feed in muddy substrates enables members of the genus Anadara to exploit a niche habitat that other bivalves tend to avoid. Predators that feed on Anadara kagoshimensis include the mallard,, the tufted duck, blue crabs, predatory snails and the common octopus. The newly settled larvae are preyed upon by the Japanese sea bass, eels and other fish as well as starfish, drills and blue crabs.