Florida is one of the largest exporters of aquarium ornamental species in the world, but trade is expanding to include harvest of herbivorous invertebrates that play important ecological roles in nature, such as grazing algae from seagrass and corals. Here, stable isotope sclerochronology is used to document life history traits of two of the most intensely harvested herbivorous gastropod species in Florida, the turbinids Lithopoma americanum and Turbo castanea. Such information is critical to assessing whether current harvest intensities are sustainable. Populations of L. americanum and T. castanea in Florida consist of rapidly maturing individuals that reach maximum sizes within 2 y and 1 y, respectively. Rapid maturation should allow these populations to recover rapidly from intense harvest, but short-lived species are also intrinsically susceptible to population collapse from recruitment failure, complicating effective management of the fishery. In addition, the short lifespans of these turbinids suggest that hobbyists may purchase replacement animals frequently, increasing fisheries pressure on natural ecosystems.