1996 年 1996 巻 50 号 p. 1-10
Sixteen species of starfish were collected at depths between 0 m and 220 m in Wakasa Bay, and the effects of sediment and depth upon the species composition were examined. The sandy area was populated by fewer Luidia quinaria and more Astropecten scoparius than the muddy area. One reason for this may be that L.quinaria preys upon sea urchins, which are abundant in the muddy area, while A.scoparius eats small bivalves, which are abundant in the sandy area. The species composition shifted abruptly in the 100-160m depth zone, while the water temperature decreased more rapidly in the 90-200m zone than in the other zones. The species sampled from the colder depth range in Wakasa Bay are geo-graphically distributed in colder regions. These results show that water temperature restricts their distribution.