A box model has been constructed for the northeastern Mediterranean Sea, where there is no reliable information on the total removal of fish by fisheries. The model utilizes survey data of biomass and these initial values are improved by a series of population dynamics methods. Once absolute values for the system components (length-weight relational growth parameters, mortality estimates, selection ogives, stomach content analysis) are established, biomass transfer within the ecosystem compartments is estimated by the food requirement of each group. Finally, after subtracting natural mortality from total mortality, the remainder is attributed to fishing mortality, which, in turn, provides information about the total catch of each species. The model is therefore independent of fisheries data but estimates the total amount of fish exploited by the fishing fleet. This feature is advantageous if, as here, one has data only from a research survey and has limited access to any other data sources.