The economic effects resulting from the diminishing catch per unit of effort (CPUE) in the nylon shrimp and squat lobster fishery off northern-central Chile from 1997 to 2000 were evaluated. A bio-technological simulation model was used that describes the physical and biological performance variables for the fishery. An economic submodel was incorporated to the original model in order to perform an integrated analysis of the crustacean fishery, including the catch and processing sub-sectors. The economic results, in conjunction with the data on catch and stock size, explained this fishery's dynamic off northern-central Chile during the study period. The total catch increased 21% between 1997 and 2000 and the final production increased 24%, but the quasi rent of the variable costs increased only 11%. The same period saw costs associated with fishing trips increase 117% and the total production cost increased 93%. The study results showed that part of the profits were lost due to the decreased biomass of both resources and the excessive increase in the average production costs, which were explained by the increased fishing trip costs. In order to obtain a better representation of the fishery's performance, economic references points should be incorporated to complement the traditional biological (biomass) and fishery (CPUE, catches) proxies