1. Introduction
Sea cucumber Apostichopus japonicus is distributedmainly in northern
China, eastern Russia, Japan, and Korea, which has become a dominant
mariculture species because of its relatively high economic value
[1]. Usually the sea cucumbers are cultured in shallow seas or ponds
without supplement feeds in China. In recent years, industrial aquaculture
of sea cucumbers has expanded rapidly becoming an important
culturing mode, in which artificial diets are needed. Some basic issues
of sea cucumber culture, such as ecological conditions, stocking density
and feed nutrition have been solved to someextent [2–5]. However, relatively
little is known about sea cucumber feeding behavior in an aquaculture
setting. Such information could be useful for designing optimal
feeding schedules to increase production and decrease food waste.
Sea cucumber collects food by extending its tentacles surrounding
its mouth. The type of tentacle is closely linked to the mode of feeding
employed by each species [6]. For example, holothurians, Psychropotes
longicauda have stubby peltate tentacles that collect sediment particles
by sweeping, whereas holothurians, Oneirophanta mutabilis have
branched digitate tentacles that collect sediment particles by raking
[7]. The tentacle structure and feeding strategy vary not only in different
species but also within same species. Cameron and Fankboner [8] observed
that the pentacula larva, juvenile, and adult life stages of
Parastichopus californicus had subtle differences in tentacle structure