スガイLunella coronata coreensis(Récluz,1853)の分布と採餌

1992年5月から1993年11月まで、広島県福山市鞆町仙酔島の磯水域で、リュウテンサザエ科のスガイについて、生息環境ならびに食性と採餌ついて調査した。これによって以下のような本種の資源生態的特牲を明かにした。付着珪藻類が最も重要な餌斜であるが、成長するにつれて海藻類も採餌するようになった。そのため幼貝は付着珪藻類の多い浅所のタイドプールに分布し、大型個体は産卵期以外は海藻類の多い深場に分布した。夜間活動型で採餌は主に夜に行われた。分布様式が冬期の集中型から春期から夏期にかけて分散型へ移行するのは、環境中の餌を積極的に利用するためである。

The distribution and foraging of the turbinid gastropod Lunella coronala coreensis in Sensui-jima Island, Hiroshima Prefecture w ere examined from May 1992 to November 1993. Stomach contents analysis showed that sessile diatoms were the most critical food resource. The shells foraged also seaweeds as they grew. Juveniles inhabited shallow areas, in particular, tide pools in which more sessile diatoms were available, whereas bigger shells inhabited deeper areas in which more seaweeds were available. They foraged mainly during the night. During the winter months, they congregated in tide pools and decreased foraging and movement. This period also coincided with cessation of growth. With the start of spring shells began to disperse and grow. This change in distribution was interpreted as their efficient utilization of food for the growing season, Matured shells were distributed up to the shallow rocky bottoms.