Scared Strong: Harnessing the Ecology of Fear to Improve Oyster Restoration

Speaker: Dr. Lee Smee
Professor of Marine and Environmental Sciences, University of South Alabama

Many prey species alter their morphology in response to predation risk, increasing survival but often at a cost to growth or reproduction. Harnessing these induced defenses could improve the success of restoration and aquaculture efforts. Eastern oysters (Crassostrea virginica) respond to chemical cues from predators and injured conspecifics by producing stronger shells. We tested whether these predator-induced defenses could be used to improve oyster survival and restoration outcomes. Exposure of oyster spat to predator cues increased shell strength by 20 to 100% and improved survival by more than 50% after one year in the field. Although induced oysters initially invested less in soft tissue growth, they reached similar sizes and tissue masses as controls within a year. We also found that shading further increased oyster survival, indicating that both predation and environmental stress influence restoration success. In parallel, we conducted bioassays to identify the predator-derived compounds that trigger shell strengthening, with the goal of developing a synthetic cue to induce defensive traits and enhance survivorship. These studies identified several candidate molecules in predator urine that may serve as the basis for such a cue. Together, these findings demonstrate that predator-induced plasticity can be leveraged to improve oyster survival and restoration success, highlighting the potential of natural chemical signals as a nontoxic tool for reducing mortality in restored and cultivated populations.

Photo: Image by Cyril from Pixabay