In many countries, traditional scientific guidance for fisheries management has been based on the population dynamics of the target stocks. Most research developed for management occurs in response to the necessity of protecting stocks from evident overfishing and loss of recruitment. To accomplish this, different strategies have been implemented through specific management measures. The complexity of analytical tools varies according to the degree of knowledge required, from general, simple population-dynamics studies to formal and complex simulation experiments, including risk and uncertainty analyses. Other management initiatives requiring scientific advice are stock conservation strategies such as fishery closures, use of excluder devices, andnatural reserves and protected areas. Recently, an ecosystem-based approach has been instituted as an alternative available for management strategies. However, even though this new approach offers more information upon which to base decisions, ecosystem-based management requires participation of all ecosystem users, including fishing fleets, which sometimes results in negative benefits for some stakeholders in order to improve ecosystem health, fishery yields, or stock recovery. The ecosystem approach also is used to evaluate the impact of fishing on the dynamics and structure of ecosystems that experience strong fishing effort. In this paper, I discuss scientific work that seeks to promote ecosystem health, conservation, and sustainable exploitation as common goals of research and management. I illustrate this approach by discussing fisheries from the littoral zone of Mexico. Several misleading scientific concepts presently form the basis for fisheries management in Mexico, and these have precipitated serious consequences for the stocks to which they are applied. These concepts include (a) the idea that fish produce eggs in excess, (b) the belief that allowing fish to reproduce at least once during their lifetime is sufficient to maintain recruitment levels, and (c) the assumption of constant natural mortality in fish stocks. Discussion of these concepts yields the conclusion that marine protected areas are probably the best choice when the goal is to manage Mexico's benthic fisheries for sustainability.
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