The northern part of the continental shelf of Yucatan, Mexico, as defined here, has a surface area of 100,000 km super(2) and supports several important tropical fisheries resources (groupers, snappers, lobsters, shrimps, among others). This contributios provides preliminary description of how this community is organized and its species linked by trophic flows. Analysis is centered on the application of the ECOPATH II model, which advantages and limitations are described, with emphasis on: (1) assumptions of model equations and (2) quality of information required. Based on the results, about half of the energy used in the community comes from primary producers (benthic and phytoplankton); the rest is imported as detritus. Total production equals 2,049 g m super(-2) year super(-1) dry weight (dw); total respiratory flows are 602 g m super(-2) year super(-1) dw; and the total flows of detritus, 395 g m super(-2) year super(-1) dw. ECOPATH II is a linear deterministic model that assumes steady-state condistions. Because of the biological basis of the model equations, ECOPATH II facilitates description of community processes and is useful for comparative studies of ecosystems. It could be modified, however, to consider the time delays inherent in ecosystem behavior as well as uncertainty in parameter estimation. Concerning input data, special attention must be given to stomach content studies, which form the basis for analysis of trophic community structure and the study of energy flow.