Food habit of chiton Acanthopleura japonica from Jogashima, Miura peninsula, Kanagawa prefecture, Japan

Abstract

We examined the food habits and ontogenetic trophic shifts of the Japanese common chiton, Acanthopleura japonica. Specimens were collected from the intertidal zone of Jogashima, Miura Peninsula, Kanagawa Prefecture, Japan. Based on gut content analysis of 18 specimens, red algae were found to be the most abundant food item（37.0%）, followed by green and brown algae（5.6% each）, bivalves（5.0%）, mites（2.6%）, and abundant abiogenic minerals（stone or rock debris）as non-food items. This gut content composition was inconsistent with that of another population from Amakusa, Kyushu, Japan; hence, the food habits of A. japonica would vary depending on habitat environments, suggesting they are non-selective omnivorous feeders. Individual variations of the gut contents did not correlate with the body length, indicating A. japonica has no ontogenetic trophic shift. Overall, we concluded that A. japonica is omnivorous without an ontogenetic trophic shift.