The range and degree of human health effects seems to vary annually and temporally in coastal regions, depending on the red tide density as well as variation in toxicity differences among dinoflagellate strains and their subsequent consumers. The Gulf of Mexico, and in particular the west coast of Florida, is the most heavily impacted by the adverse health and environmental effects of nearly annual "K. brevis" blooms. This region has suffered significant economic losses in local communities that rely on tourism and recreational fishing along with bad publicity over the years. Shellfish poisonings have been known about in Florida since the 1880s, although the cause was not identified as "K. brevis" until 1960.