Movement and orientation patterns in the commercial sea cucumber<i>Parastichopus californicus</i>(Stimpson) (Holothuroidea: Aspidochirotida)

Abstract

The commercial sea cucumber Parastichopus californicus was tagged in situ, and its daily summer activity patterns followed over periods of up to two months. On bedrock covered with shell rubble, cobbles, and boulders, P. californicus crawled an average of 3.9 m/d. Long term movement on gently sloping substrata showed no directional bias. Tidal currents in the study areas had no influence upon either orientation or locomotory direction. On vertical rock surfaces, P. californicus has a negative geotropic orientation which we conclude is associated with opportunistic suspension feeding. On horizontal substrata, feeding and locomotory behaviour in P. californicus are simultaneous activities, and we suggest that the apparent random activity patterns in these sea cucumbers is mediated by an evenly distributed and renewable source of detrital food.