IMPORTANCE OF THE GUILD CONCEPT TO FISHERIES RESEARCH AND MANAGEMENT

The concept of the guild has appealed to fisheries researchers and man agers for simplifying analysis and assisting in the prediction of comm unity change. Guilds have been developed based on reproduction, feedin g, habitat use, and morphology. In most published accounts, guilds wer e used to describe a community change in response to some environmenta l perturbation (e.g., stream habitat modification or siltation). Membe rs of a guild are often expected to react similarly to environmental c hange. However, little evidence exists to support the extrapolation of population changes in one guild member to that of other members of th e same guild. It may be more reasonable to assume that the combined ab undance of all species in a guild can more accurately reflect changes in their primary resource or a limiting factor. Thus, we suggest that guilds reflect the characteristics of a super-species-a unit that resp onds to environmental change in a more predictable manner than individ ual species. We recommend that guilds be developed based on critical e nvironmental variables that are most influential in determining commun ity composition. Also, the use of guild definitions needs to be evalua ted with long-term data sets to ascertain their true ability to descri be community dynamics.