Tarpon fishing offers the opportunity to pursue a narrative of environmental and sport history that focuses on the mutuality between ecology and development. Angling for tarpon illustrates the capacity of an offshore, sporting species to alter the landscape and growth of an entire region. Tarpon fishing reshaped the southwest coast of Florida. In the Charlotte Harbor region, the confluence of human and nonhuman species catalyzed a sporting enterprise that grew dramatically in the late nineteenth and early twentieth centuries. Fishing for tarpon in the Gulf of Mexico was almost exclusively a sporting pursuit, because the unpalatable tarpon had little commercial value. The convergence of the sporting and environmental histories of southwest Florida, the demographics of fishermen and fish, and the development of sporting industries regionally and nationally all provide evidence of the close ecological mutuality that defined tarpon angling during its peak years. On account of features of the fish's annual and life cycle, the region, and the sport, this fishing seemed not to overtax populations of the fish themselves.