Do pedicellariae act as a pursuit-deterrent cue?

The response of Chromis atripectoralis and Pseudanthias hypselosoma to water-borne cues from the sea urchin Tripneustes gratilla before and after it has been induced to release pedicellariae, and to seawater with no cue. When no sea urchin was present some fish individuals preferred one side of the flume over another (>60% of time in one channel). The data with a cue thus indicate time (%) spent in treatment water when the sea urchin was on their preferred side.