About Asterias amurensis Lutken, 1871
Asterias amurensis Lutken, 1871 can grow up to 50 cm in diameter, though this is an exceptional size. Its arms usually reach 16.1 cm in length, and the ratio of arm length to central disc radius ranges from 3.6:1 to 5.9:1. It has five arms and a small central disc, and can be told apart from similar species by the distinctive upturned tips of its arms. Its entire underside is yellow, while its dorsal side displays a wide range of colors: orange to yellow, and occasionally red or purple. Its arms are unevenly covered with small, jagged-edged spines. These spines line the groove that holds the tube feet, and join together in a fan-like shape at the mouth. This species prefers slightly cold environments of around 7–10 °C (45–50 °F); another reported optimum temperature range is 9–13 °C (48–55 °F). Sources differ on its temperature tolerance: one source records a tolerance range of 0–25 °C (32–77 °F), while another records 5–20 °C (41–68 °F). It can tolerate a broad range of salinities, from 18.7–41.0 ppt, and can survive in estuaries. It has been found at a maximum depth of 220 m, and prefers shallow, sheltered areas. Adults occur across a wide variety of substrates, including kelp forests, mud, sand, pebbles, rock, flotsam, fishing nets, and artificial substrates. It is not found in areas with high wave action or on reefs. This species is considered useful in traditional Chinese medicine, and is included in the 2015 Pharmacopoeia of the People's Republic of China.
