The distribution patterns of some large benthic epifauna on muddy sand in the Irish Sea were surveyed using an underwater video-camera system in July and August 1982. Information was stored on videotape and later analysed using a statistical method for the description of segregation. This analysis was then used to attempt to deduce whether the animals were distributed primarily in response to competition for food, by comparing the segregation patterns of animals with different feeding habits. Animals of different species were nearly always significantly segregated from each other. The implications of this finding for some theories of community structure are discussed briefly. Detritivorous animals segregated most strongly, predaceous animals less so. It is suggested that although competition for food may be a factor affecting segregation in some cases, it does not seem to act as an overall determining factor for the whole epifaunal assemblage. gated but mingled, then there must exist some cooperative or dependent effect (e.g. commensalism or parasitism) that keeps individuals of the two species together.
If the segregation is strongest between species with a similar feeding strategy, then it seems likely that competition for food may be an important factor. If, however, this segregation is strongest between species with different feeding habits, then it seems unlikely that competition for food can be an important causative factor and other factors must be involved.
The distribution patterns of some large, motile benthic animals were studied by surveying an area of sea bed with an underwater video-camera. Resulting data were recorded and later analysed by a statistical method for the description of segregation. The feeding habits of the commoner animals were then obtained from the literature on this topic.