Community Ecology of Offshore Demersal Fish Assemblages

Some ecological information about offshore demersal fish communities is reviewed. Research on the structure of fish communities is popular, and many works have been carried out in fresh water, coral reef, and coastal habitats. Studies of offshore demersal fish communities are relatively scarce and descriptive. Many commercially important species inhabit in offshore waters, and recently community-level studies have been required for the management of fishery stocks. Characteristics of the communities were described on some features, e. g., density, biomass, species diversity and rank-abundance diagram. Gradient analyses along water depth revealed some trends of such features characterizing the community structure. Many current studies examined the food of demersal fish. Two types of feeding guilds, benthic feeding and benthopelagic feeding, were recognized, and the latter was quantitatively important for energy input into demersal fish communities. Recent publications scrutinized the pattern of resource use examining the niche for food and space. Such works on resource partitioning showed both niche overlap and niche segregation by food, and little evidence indicated the existence of interspecific competition.