The Mexican shrimp fishery comprises a sequential fishery: an inshore fleet (IF) using cast nets and targeting juvenile shrimps; and the offshore fleet (OF) using trawler boats targeting adult shrimps. The main target species are brown, blue and white shrimps. Conventional aged-structured models are used to advice management of this fishery assuming constant M (natural mortality) and q (catchability) which do not accord with the dynamics of a sequential fishery. In our analysis we compare both, conventional and M and q constant aged-structured models, for the shrimp fishery (2014-15) in southern Gulf of California using as state variables fleet profits, recruitment (R) and spawning stock (SSB); finally we apply a management criteria of Maximum Economic Yield (MEY) to the OF. The constant M scenario showed a high economic and biological variables (R&SSB) overestimation because low M values for earlier stages. The constant q scenario showed a global underestimation mainly in IF profits and biological variables. Using both constant coefficients resulted in a higher overestimation of OF profits and biological variables, with an underestimation in inshore fleet profits. The MEY criteria over the conventional model showed -60% trawler effort and a biological and economical fishery gain. In contrast, the model using constant M and q showed overestimated OF profits and biological variables. On the other hand, it tends to underestimate IF profits. In conclusion assumption of constant M and q values used in sequential fishery resulted in effort, economic and biological biased estimates which may have undesired consequences for fishery management.