Title: Mexican Abalone and Lobster Extractions At Baja California Peninsula Considering Illegal Catch; Approach to Face The Zero Illegal Catch Assumption Authors: Mario Ramade-Villanueva, FEDERACION REGIONAL DE SOCIEDADES COOPERATIVAS DE PRODUCCION PESQUERA "BAJA CALIFORNIA" (Mexico) Pablo Delmonte-Luna, CENTRO INTERDISCIPLINARIO DE CIENCIAS MARINAS - IPN (Mexico) Alfredo Hernandez-Llamas, CENTRO DE INVESTIGACIONES BIOLOGICAS DEL NOROESTE (Mexico) Francisco Arreguin-Sanchez, CENTRO INTERDISCIPLINARIO DE CIENCIAS MARINAS - IPN (Mexico) German Ponce-Diaz, CENTRO INTERDISCIPLINARIO DE CIENCIAS MARINAS - IPN (Mexico) Abstract: The official catch records generally are carried out in the landing operations. There three categories of fishing that are not included in landings; illegal, unreported and unregulated catch (IUU) and are considered like lack of information. It is necessary, to consider these categories of fishing to know the true impact of the fishing upon the fisheries resources and then propose adequate management measures. In this paper illegal fishing of abalone and lobster from western coast of Baja California peninsula, Mexico is analyzed in order to estimate the problem magnitude. From official records of landings and information of illegal fishing reports we do an estimation of total extraction of these resources using Montecarlo´s simulation method.