Feeding habits of asteroids, Luidia quinaria and Astropecten scoparius, in Ise Bay, Central Japan

Abstract

Feeding habits of the two asteroids dominant in Ise Bay, Luidia quinaria and Astropecten scoparius, were examined as regards their temporal and spatial distributions and also the oxygen-poor water in the bay, based on megabenthos samples collected in the bay from November 1996 to November 1997. Luidia quinaria was distributed widely in the whole part of the bay while A. scoparius was mainly found in the southern part around the bay mouth area. Analysis of the stomach contents of these asteroids demonstrated that L. quinaria preferred to ingest echinoderm, particularly an ophiuroid, Ophiura kinbergi, that occupied approximately 60% of the percentage total food items; while the stomach contents of A. scoparius were dominated by molluscs, a minute gastropod Voorwindia paludinoides and a bivalve Alvenius ojianus, which occupied approximately 59% and 33% of the percentage of total food items, respectively. The differences in the feeding habits of these asteroids may be due to their distribution pattern, which may be determined by the differences in sediment characteristics. Distribution and feeding habits of L. quinaria in summer may be affected by the occurrence of oxygen-poor water.