A long-held paradigm is that estuaries are important to the welfare of estuarine-dependent coastal fisheries, providing spawning areas, suitable salinity gradients for development, protection from predators, and food. Many publications link the beneficial nature of estuaries with fisheries production and decry human activities that modify habitat, and therefore potentially decrease fisheries production. However, what if the water quality of the estuary, often human-driven, results in less than suitable habitat for coastal fisheries productivity, both in the estuary and in the adjacent offshore waters? Finding the data to support relationships (positive and negative) among estuaries and coastal fisheries production is difficult because of inadequate data, highly variable data, or data with no clear linkages to processes. Hughes et al. (1), however, amassed a dense and multifaceted database of declining estuarine water quality in the form of worsening hypoxia to declines of fish diversity, reduced estuarine habitat suitability, and declines in offshore fisheries. The authors defend a plausible mechanism across the landsea interface.Relationships among hypoxic waters and fisheries productivity (either catch per unit effort or landings) remain as elusive as relationships of nitrogen loading and fisheries productivity. Efforts to understand these ocean trophic models shifted over the 20th century from agricultural models of food stimulated by nutrients that feed higher primary producer standing stocks and secondary production to concerns of higher N and P loads into water bodies, excess phytoplankton biomass, and the deleterious effects of eutrophication, including harmful algal blooms and hypoxia ( Fig. 1) (2-6).A meta-analysis by Micheli (7) of 47 food webs (natural and experimental) verified a relationship between nitrogen loading and primary production but not necessarily standing stocks of secondary consumers in the form of fisheries. Breitburg et al. (8) followed with a broad global analysis of 30 estuaries and semienclosed seas and found few strong relationships between N loading and fisheries production and hypoxia and fisheries production. Their divisions for fisheries were pelagic planktivores, benthopelagics, and benthics. Fisheries landings were positively related to N loading only for the benthopelagics and pelagics. None were related to the percent of the bottom water that was hypoxic.On more local or regional scales, however, there are documented decreases in landings or catch per unit effort with increase in area of hypoxia. Cod landings in the Baltic decline with an increase in stratification that affects the buoyancy of cod eggs so that they do not reach suitable habitat for development and with an increase in volume of hypoxic bottom-water that negatively affects survivability (9, 10). A similar decrease in cod landings in the western Atlantic is potentially related to increasing nutrient loads in the St. Lawrence River estuary and subsequent hypoxia (11,12).The bottom-waters of the northern Gulf o...